What the Einstein Relations Tell Us
|
|
- Delphia Antonia Morton
- 6 years ago
- Views:
Transcription
1 What the Einstein Relations Tell Us 1. The rate of spontaneous emission A21 is proportional to υ 3. At higher frequencies A21 >> B(υ) and all emission is spontaneous. A 21 = 8π hν3 c 3 B(ν) 2. Although they came from different points of view (one kinetic looking at the rate of change of numbers of molecules and the other from attenuation in intensity at steady-state). The Einstein coefficient B(υ) for stimulated absorption must be related to the molar extinction coefficient, ε(υ) in the Beer-Lambert Law at any given wavelength or frequency. 3. The rate of spontaneous emission A21 is related to the constant of stimulated absorption (absorption) and stimulated emission. Stronger something absorbs the stronger will be the emission.
2 Jablonski Diagram Singlet State Manifold Internal Conversion Intersystem Crossing Triplet State depicts various radiative and nonradiative processes that can take place between electronic states. Ground Electronic State, S0 Red-shifted fluorescence Red-shifted phosphorescence Absorption of radiation
3 Intrinsic Fluorescence Lifetime ln N 2 Short pulse of light N 2 time How the intensity of fluorescence decreases over time (when excitation stops) due only to spontaneous emission (it assumes stimulated emission is neglible). y = mx + b equation of a straight line By definition we equate the rate of fluorescence to an intrinsic lifetime τ. Nt d[n 2 ] dt d[n 2 ] [N 2 ] d[n 2 ] N 0 [N 2 ] = A 21 [N 2 ] = A 21 dt = t t=0 ln N t N 0 = A 21 t N 2 (t) = N 0 e ( A 21t) A 21 = 1 τ A 21 dt time Exponential Decay of Excited State N 2 (t) = N 0 e t/τ
4 N 2 Fluorescence Lifetime time Exponential Decay of Excited State N 2 (t) = N 0 e t/τ Points: Because there are other non-radiative pathways (internal conversion, intersystem crossing, quenching, etc.) for to rid molecules from the excited state 1/τ = A 21 is for molecules that show only deexcitation via fluorescence. Since the intensity of radiation is proportional to the number of excited state molecules per unit volume thus we can transform our equation to one that is experimentally useful. I(t) A 21 = k f = rate of fluorescence = 1/τ Emitted Intensity of Fluorescence I(t) True Decay time Exponential Decay of Excited State I(t) = I 0 e k f t = I 0 e t/τ
5 Non-Radiative Processes That Impact S1 Population Levels and Fluorescence. 1. Internal Conversion: excitation energy in S1 is lost by collision of excited state molecules with the solvent or by dissipation of energy as heat through vibrational modes in the excited to ground state. 2. Quenching: De-excitation resulting from collisions with certain types of molecules that can quench or remove energy from the excited singlet state. 3. Intersystem Crossing: small degree of forbidden spin exchange converts excited state singlet to triplet state which can convert to ground state by phosphoresance or by internal conversion. All of these processes serve to remove energy from the excited singlet state and therefore will decrease fluorescence intensity and quantum yield.
6 Rate Equations To Describe Fluorescence Process Reaction Rate Excitation S0 + hυ S1 Ia Fluorescence S1 S0 + hυ A21[S1] Quenching S1 + Q S0 + Q kq[s1][q] Internal Conversion Intersystem Crossing S1 S0 S1 T1 kic[s1] kisc[s1] Quenching, internal conversion and ISC are non-radiative pathways. Now let s analyze how the excited state population, S2 changes under conditions of steady state----constant illumination. We will sum the rates up and down and relate it to the Fluorescence intensity, IFluorescence.
7 Non-Radiative Processes And Fluorescence From the Einstein equations we can write the intensity of fluorescence as: I F luorescence = A 10 [S 1 ] d[s 1 ] dt = 0 = I a A 10 [S 1 ] k ic [S 1 ] k isc [S 1 ] k q [Q][S 1 ] = I a (A 10 [S 1 ] + k ic [S 1 ] + k isc [S 1 ] + k q [Q][S 1 ]) = I a [S 1 ](A 10 + k ic + k isc + k q [Q]) = I a [S 1] τ F I is the intensity of fluorescence, A 10 is the spontaneous emission coefficient (the rate constant if you will) and [S 1 ] is concentration of excited state molecules. Now we write the rate equation for changes in concentration of excited state molecules, S 1 under steady-state conditions (constant illumination let s say). Let s define: 1 τ F = A 10 + k ic + k isc + k q [Q] Now solve for [S1] and insert it into our original expression: IFluorescence = A10 [S1] I F luorescence = A 10 I a τ F = A 10 I A A 10 + k ic + k isc + k q [Q]
8 Quantum Yield = ΦF It is useful to define the a quantity which is the ratio of the number of photons emitted by fluorescence divided by the total number of photons absorbed to generate the excited state. It is called the quantum yield I F luorescence = A 10 I a τ F = A 10 I A A 10 + k ic + k isc + k q [Q] Φ F = I F I a = photons emitted photons absorbed = A 10 A 10 + k ic + k isc + k q [Q] = τ F τ 0 The quantum yield describes how efficient the radiative pathway is (or how the non-radiative pathways may dominate. If there are no nonradiative pathways then the quantum can be = 1 (rare if ever).
9 Instruments
10 Experimental Measurement of Fluorescence
11 The Fluorescence Spectrum With few exceptions, the fluorescence excitation spectrum of a single fluorophore species in dilute solution is identical to its absorption spectrum. Under the same conditions, the fluorescence emission spectrum is independent of the excitation wavelength, because all fluorescence occurs from the v = 0 vibrational level of the excited state. The Stokes shift is the gap between the maximum of the first absorption band and the maximum of the fluorescence spectrum Fluorescence Intensity Fluorescein molecule Stokes Shift is 25 nm 495 nm 520 nm Wavelength
Molecular Luminescence. Absorption Instrumentation. UV absorption spectrum. lg ε. A = εbc. monochromator. light source. Rotating mirror (beam chopper)
Molecular Luminescence Absorption Instrumentation light source I 0 sample I detector light source Rotating mirror (beam chopper) motor b sample I detector reference I 0 UV absorption spectrum lg ε A =
More informationSinglet. Fluorescence Spectroscopy * LUMO
Fluorescence Spectroscopy Light can be absorbed and re-emitted by matter luminescence (photo-luminescence). There are two types of luminescence, in this discussion: fluorescence and phosphorescence. A
More informationLABORATORY OF ELEMENTARY BIOPHYSICS
LABORATORY OF ELEMENTARY BIOPHYSICS Experimental exercises for III year of the First cycle studies Field: Applications of physics in biology and medicine Specialization: Molecular Biophysics Fluorescence
More informationChemistry 2. Molecular Photophysics
Chemistry 2 Lecture 12 Molecular Photophysics Assumed knowledge Electronic states are labelled using their spin multiplicity with singlets having all electron spins paired and triplets having two unpaired
More informationPHOTOCHEMISTRY NOTES - 1 -
- 1 - PHOTOCHEMISTRY NOTES 1 st Law (Grotthus-Draper Law) Only absorbed radiation produces chemical change. Exception inelastic scattering of X- or γ-rays (electronic Raman effect). 2 nd Law (Star-Einstein
More information10. 6 Photochemistry. Out-class reading: Levine, pp photochemistry
Out-class reading: Levine, pp. 800-804 photochemistry 6.1 Brief introduction of light 1) Photochemistry The branch of chemistry which deals with the study of chemical reaction initiated by light. 2) Energy
More informationExcited State Processes
Excited State Processes Photophysics Fluorescence (singlet state emission) Phosphorescence (triplet state emission) Internal conversion (transition to singlet gr. state) Intersystem crossing (transition
More informationCD Basis Set of Spectra that is used is that derived from comparing the spectra of globular proteins whose secondary structures are known from X-ray
CD Basis Set of Spectra that is used is that derived from comparing the spectra of globular proteins whose secondary structures are known from X-ray crystallography An example of the use of CD Modeling
More informationXV 74. Flouorescence-Polarization-Circular-Dichroism- Jablonski diagram Where does the energy go?
XV 74 Flouorescence-Polarization-Circular-Dichroism- Jablonski diagram Where does the energy go? 1) Excite system through A Absorbance S 0 S n Excite from ground excited singlet S = 0 could be any of them
More informationComplex Reaction Mechanisms Chapter 36
Reaction Mechanisms: Complex Reaction Mechanisms Chapter 36 Reaction mechanism is a collection o elementary (one step) reactions that would add up to result in the overall reaction. Generally elementary
More informationIntroduction ENERGY. Heat Electricity Electromagnetic irradiation (light)
Photochemistry Introduction ENERGY Heat Electricity Electromagnetic irradiation (light) Vision: Triggered by a photochemical reaction Is red in the dark? The answer must be NO - Since what we see as colour
More informationGeneration of light Light sources
Generation of light Light sources Black-body radiation Luminescence Luminescence Laser Repetition Types of energy states in atoms and molecules are independent (not coupled) Energy states are non-continuous,
More informationToday: general condition for threshold operation physics of atomic, vibrational, rotational gain media intro to the Lorentz model
Today: general condition for threshold operation physics of atomic, vibrational, rotational gain media intro to the Lorentz model Laser operation Simplified energy conversion processes in a laser medium:
More informationFluorescence (Notes 16)
Fluorescence - 2014 (Notes 16) XV 74 Jablonski diagram Where does the energy go? Can be viewed like multistep kinetic pathway 1) Excite system through A Absorbance S 0 S n Excite from ground excited singlet
More informationFigure 1 Relaxation processes within an excited state or the ground state.
Excited State Processes and Application to Lasers The technology of the laser (Light Amplified by Stimulated Emission of Radiation) was developed in the early 1960s. The technology is based on an understanding
More informationLecture 3: Light absorbance
Lecture 3: Light absorbance Perturbation Response 1 Light in Chemistry Light Response 0-3 Absorbance spectrum of benzene 2 Absorption Visible Light in Chemistry S 2 S 1 Fluorescence http://www.microscopyu.com
More informationIntroduction to Fluorescence Spectroscopies I. Theory
March 22, 2006; Revised January 26, 2011 for CHMY 374 Adapted for CHMY 362 November 13, 2011 Edited by Lauren Woods December 2, 2011 17mar14, P.Callis; 1feb17 P. Callis, 29jan18 P. Callis Introduction
More informationChapter 17: Fundamentals of Spectrophotometry
Chapter 17: Fundamentals of Spectrophotometry Spectroscopy: the science that deals with interactions of matter with electromagnetic radiation or other forms energy acoustic waves, beams of particles such
More informationFluorescence 2009 update
XV 74 Fluorescence 2009 update Jablonski diagram Where does the energy go? Can be viewed like multistep kinetic pathway 1) Excite system through A Absorbance S 0 S n Excite from ground excited singlet
More informationMie vs Rayleigh. Sun
Mie vs Rayleigh Sun Chemists Probe Various Energy Levels of Molecules With Appropiate Energy Radiation It is convenient (and accurate enough for our purposes) to treat a molecule or system of molecules
More informationQuantum Electronics/Laser Physics Chapter 4 Line Shapes and Line Widths
Quantum Electronics/Laser Physics Chapter 4 Line Shapes and Line Widths 4.1 The Natural Line Shape 4.2 Collisional Broadening 4.3 Doppler Broadening 4.4 Einstein Treatment of Stimulated Processes Width
More informationChapter 17: Fundamentals of Spectrophotometry
Chapter 17: Fundamentals of Spectrophotometry Spectroscopy: the science that deals with interactions of matter with electromagnetic radiation or other forms energy acoustic waves, beams of particles such
More informationRotation and vibration of Molecules
Rotation and vibration of Molecules Overview of the two lectures... 2 General remarks on spectroscopy... 2 Beer-Lambert law for photoabsorption... 3 Einstein s coefficients... 4 Limits of resolution...
More informationChapter 15 Molecular Luminescence Spectrometry
Chapter 15 Molecular Luminescence Spectrometry Two types of Luminescence methods are: 1) Photoluminescence, Light is directed onto a sample, where it is absorbed and imparts excess energy into the material
More information1 Fluorescence Resonance Energy Transfer
1 Fluorescence Resonance Energy Transfer FRET is nominally the non-radiative transfer of energy from a donor molecule to the acceptor molecule, therefore the signature of FRET is quenching of the low energy
More informationAdvanced Organic Chemistry Chm 512/412 Spring Handout I Photochemistry Part 1. Photophysical Processes Quenching Alkene cis-trans Isomerization
Advanced rganic Chemistry Chm 512/412 Spring 2010 Handout I Photochemistry Part 1 Photophysical Processes Quenching Alkene cis-trans Isomerization Importance of Photochemistry/Photophysics rganic Synthesis
More informationChap. 12 Photochemistry
Chap. 12 Photochemistry Photochemical processes Jablonski diagram 2nd singlet excited state 3rd triplet excited state 1st singlet excited state 2nd triplet excited state 1st triplet excited state Ground
More informationMolecular spectroscopy
Molecular spectroscopy Origin of spectral lines = absorption, emission and scattering of a photon when the energy of a molecule changes: rad( ) M M * rad( ' ) ' v' 0 0 absorption( ) emission ( ) scattering
More informationLaser Detection Techniques
Laser Detection Techniques K.-H. Gericke Institute for Physical Chemistry University Braunschweig E 2 E 1 = hn, λ = c /n Lambert-Beer Law Transmittance of the sample:: T = I / I 0 T = e -snl = e -α, where
More informationLuminescence spectroscopy
Febr. 203 Luminescence spectroscopy Biophysics 2 nd semester Józse Orbán University o Pécs, Department o Biophysics Deinitions, laws FUNDAMENTALS o SPECTROSCY review - Spectral types (absorbtion/emission
More information1. Photoreduction of Benzophenone in 2-Propanol
1. Photoreduction of Benzophenone in 2-Propanol Topic: photochemistry, photophysics, kinetics, physical-organic chemistry Level: undergraduate physical chemistry Time: 2 x 2 hours (separated by ~24 hours)
More informationsingle-molecule fluorescence resonance energy transfer
single-molecule fluorescence resonance energy transfer (2) determing the Förster radius: quantum yield, donor lifetime, spectral overlap, anisotropy michael börsch 26/05/2004 1 fluorescence (1) absorbance
More informationOptical Spectroscopy 1 1. Absorption spectroscopy (UV/vis)
Optical Spectroscopy 1 1. Absorption spectroscopy (UV/vis) 2 2. Circular dichroism (optical activity) CD / ORD 3 3. Fluorescence spectroscopy and energy transfer Electromagnetic Spectrum Electronic Molecular
More informationChemistry Instrumental Analysis Lecture 3. Chem 4631
Chemistry 4631 Instrumental Analysis Lecture 3 Quantum Transitions The energy of a photon can also be transferred to an elementary particle by adsorption if the energy of the photon exactly matches the
More informationFluorescence spectra of 1-Pyrenebutyric acid, concentration dependence and dynamic quenching phenomena
Practicum Spectroscopy Fall 2010 Fluorescence spectra of 1-Pyrenebutyric acid, concentration dependence and dynamic quenching phenomena LUM Jorge Ferreiro, study degree Chemistry, 5 th semester, fjorge@student.ethz.ch
More informationFluorescence Excitation and Emission Fundamentals
Fluorescence Excitation and Emission Fundamentals Fluorescence is a member of the ubiquitous luminescence family of processes in which susceptible molecules emit light from electronically excited states
More informationChapter 6 Photoluminescence Spectroscopy
Chapter 6 Photoluminescence Spectroscopy Course Code: SSCP 4473 Course Name: Spectroscopy & Materials Analysis Sib Krishna Ghoshal (PhD) Advanced Optical Materials Research Group Physics Department, Faculty
More informationWavelength λ Velocity v. Electric Field Strength Amplitude A. Time t or Distance x time for 1 λ to pass fixed point. # of λ passing per s ν= 1 p
Introduction to Spectroscopy (Chapter 6) Electromagnetic radiation (wave) description: Wavelength λ Velocity v Electric Field Strength 0 Amplitude A Time t or Distance x Period p Frequency ν time for 1
More informationLuminescence Spectroscopy Excitation is very rapid (10-15 s). Vibrational relaxation is a non-radiational process. It involves vibrational levels of
Luminescence Spectroscopy Excitation is very rapid (10-15 s). Vibrational relaxation is a non-radiational process. It involves vibrational levels of the same electronic state. The excess of vibrational
More informationGeneral Considerations 1
General Considerations 1 Absorption or emission of electromagnetic radiation results in a permanent energy transfer from the emitting object or to the absorbing medium. This permanent energy transfer can
More informationChapter 3. Electromagnetic Theory, Photons. and Light. Lecture 7
Lecture 7 Chapter 3 Electromagnetic Theory, Photons. and Light Sources of light Emission of light by atoms The electromagnetic spectrum see supplementary material posted on the course website Electric
More informationModern Optical Spectroscopy
Modern Optical Spectroscopy With Exercises and Examples from Biophysics and Biochemistry von William W Parson 1. Auflage Springer-Verlag Berlin Heidelberg 2006 Verlag C.H. Beck im Internet: www.beck.de
More informationMolecular Luminescence Spectroscopy
Molecular Luminescence Spectroscopy In Molecular Luminescence Spectrometry ( MLS ), molecules of the analyte in solution are excited to give a species whose emission spectrum provides information for qualitative
More informationFluorescence Polarization Anisotropy FPA
Fluorescence Polarization Anisotropy FPA Optics study of light Spectroscopy = light interacts the study of the interaction between matter & electro-magnetic radiation matter Spectroscopy Atomic Spectroscopy
More informationFluorescence Workshop UMN Physics June 8-10, 2006 Quantum Yield and Polarization (1) Joachim Mueller
Fluorescence Workshop UMN Physics June 8-10, 2006 Quantum Yield and Polarization (1) Joachim Mueller Quantum yield, polarized light, dipole moment, photoselection, dipole radiation, polarization and anisotropy
More informationChapter 11. Basics in spin-orbit couplings
1- The Jablonski diagram (or the state diagram of diamagnetic molecules) 2- Various natures of excited states and basics in molecular orbitals 3- Vibronic coupling and the Franck-Condon term 4- Excited
More informationExcited States in Organic Light-Emitting Diodes
Excited States in Organic Light-Emitting Diodes The metal-to-ligand charge transfer (MLCT) excited states of d 6 π coordination compounds have emerged as the most efficient for solar harvesting and sensitization
More informationWhat is spectroscopy?
Absorption Spectrum What is spectroscopy? Studying the properties of matter through its interaction with different frequency components of the electromagnetic spectrum. With light, you aren t looking directly
More informationIntroduction to Sources: Radiative Processes and Population Inversion in Atoms, Molecules, and Semiconductors Atoms and Molecules
OPTI 500 DEF, Spring 2012, Lecture 2 Introduction to Sources: Radiative Processes and Population Inversion in Atoms, Molecules, and Semiconductors Atoms and Molecules Energy Levels Every atom or molecule
More informationModel Answer (Paper code: AR-7112) M. Sc. (Physics) IV Semester Paper I: Laser Physics and Spectroscopy
Model Answer (Paper code: AR-7112) M. Sc. (Physics) IV Semester Paper I: Laser Physics and Spectroscopy Section I Q1. Answer (i) (b) (ii) (d) (iii) (c) (iv) (c) (v) (a) (vi) (b) (vii) (b) (viii) (a) (ix)
More informationReflection = EM strikes a boundary between two media differing in η and bounces back
Reflection = EM strikes a boundary between two media differing in η and bounces back Incident ray θ 1 θ 2 Reflected ray Medium 1 (air) η = 1.00 Medium 2 (glass) η = 1.50 Specular reflection = situation
More informationCHEM Outline (Part 15) - Luminescence 2013
CHEM 524 -- Outline (Part 15) - Luminescence 2013 XI. Molecular Luminescence Spectra (Chapter 15) Kinetic process, competing pathways fluorescence, phosphorescence, non-radiative decay Jablonski diagram
More informationLuminescence. Photoluminescence (PL) is luminescence that results from optically exciting a sample.
Luminescence Topics Radiative transitions between electronic states Absorption and Light emission (spontaneous, stimulated) Excitons (singlets and triplets) Franck-Condon shift(stokes shift) and vibrational
More informationAssumed knowledge. Chemistry 2. Learning outcomes. Electronic spectroscopy of polyatomic molecules. Franck-Condon Principle (reprise)
Chemistry 2 Lecture 11 Electronic spectroscopy of polyatomic molecules Assumed knowledge For bound excited states, transitions to the individual vibrational levels of the excited state are observed with
More informationChapter 13. Phys 322 Lecture 34. Modern optics
Chapter 13 Phys 3 Lecture 34 Modern optics Blackbodies and Lasers* Blackbodies Stimulated Emission Gain and Inversion The Laser Four-level System Threshold Some lasers Pump Fast decay Laser Fast decay
More informationReflection = EM strikes a boundary between two media differing in η and bounces back
Reflection = EM strikes a boundary between two media differing in η and bounces back Incident ray θ 1 θ 2 Reflected ray Medium 1 (air) η = 1.00 Medium 2 (glass) η = 1.50 Specular reflection = situation
More informationLAB #3: FLUROESCENCE SPECTROSCOPY AND ELECTRON TRANSFER (This lab is adapted from the U of MN Phsyical Chemistry lab manual)
Chemistry 372 Gustavus Adolphus College A. Purpose LAB #3: FLUROESCENCE SPECTROSCOPY AND ELECTRON TRANSFER (This lab is adapted from the U of MN Phsyical Chemistry lab manual) In this experiment, you will
More informationLecture 0. NC State University
Chemistry 736 Lecture 0 Overview NC State University Overview of Spectroscopy Electronic states and energies Transitions between states Absorption and emission Electronic spectroscopy Instrumentation Concepts
More informationMolecular Fluorescence Spectroscopy Jose Hodak
Molecular Fluorescence Spectroscopy Jose Hodak Introduction This notes were prepared based mainly on Bernard Valeur molecular luorescence book. I would recommend this book to the students who need learn
More informationCHAPTER 13 Molecular Spectroscopy 2: Electronic Transitions
CHAPTER 13 Molecular Spectroscopy 2: Electronic Transitions I. General Features of Electronic spectroscopy. A. Visible and ultraviolet photons excite electronic state transitions. ε photon = 120 to 1200
More informationRadiation in the Earth's Atmosphere. Part 1: Absorption and Emission by Atmospheric Gases
Radiation in the Earth's Atmosphere Part 1: Absorption and Emission by Atmospheric Gases Electromagnetic Waves Electromagnetic waves are transversal. Electric and magnetic fields are perpendicular. In
More informationMODERN OPTICS. P47 Optics: Unit 9
MODERN OPTICS P47 Optics: Unit 9 Course Outline Unit 1: Electromagnetic Waves Unit 2: Interaction with Matter Unit 3: Geometric Optics Unit 4: Superposition of Waves Unit 5: Polarization Unit 6: Interference
More informationAula 5 e 6 Transferência de Energia e Transferência de Elétron Caminhos de espécies fotoexcitadas
Fotoquímica Aula 5 e 6 Transferência de Energia e Transferência de Elétron Prof. Amilcar Machulek Junior IQ/USP - CEPEMA Caminhos de espécies fotoexcitadas 1 Diagrama de Jablonski S 2 Relaxation (τ < 1ps)
More informationChem 442 Review of Spectroscopy
Chem 44 Review of Spectroscopy General spectroscopy Wavelength (nm), frequency (s -1 ), wavenumber (cm -1 ) Frequency (s -1 ): n= c l Wavenumbers (cm -1 ): n =1 l Chart of photon energies and spectroscopies
More informationSupporting Information
Supporting Information Mulifunctional Dendritic Emitter: Aggregation-Induced Emission Enhanced, Thermally Activated Delayed Fluorescent Material for Solution- Processed Multilayered Organic Light-Emitting
More informationA Fluorometric Analysis of Quinine in Tonic Water
A Fluorometric Analysis of Quinine in Tonic Water Introduction In this Laboratory Exercise, we will determine the amount of quinine in Tonic Water using a fluorometric analysis. Fluorescence Spectroscopy
More informationFluorescence Workshop UMN Physics June 8-10, 2006 Basic Spectroscopic Principles Joachim Mueller
Fluorescence Workshop UMN Physics June 8-10, 2006 Basic Spectroscopic Principles Joachim Mueller Fluorescence, Light, Absorption, Jablonski Diagram, and Beer-Law First stab at a definition: What is fluorescence?
More informationLecture 15: Optoelectronic devices: Introduction
Lecture 15: Optoelectronic devices: Introduction Contents 1 Optical absorption 1 1.1 Absorption coefficient....................... 2 2 Optical recombination 5 3 Recombination and carrier lifetime 6 3.1
More informationWhat dictates the rate of radiative or nonradiative excited state decay?
What dictates the rate of radiative or nonradiative excited state decay? Transitions are faster when there is minimum quantum mechanical reorganization of wavefunctions. This reorganization energy includes
More informationElectronic Spectra of Complexes
Electronic Spectra of Complexes Interpret electronic spectra of coordination compounds Correlate with bonding Orbital filling and electronic transitions Electron-electron repulsion Application of MO theory
More informationDepartment of Chemistry Physical Chemistry Göteborg University
Department of Chemistry Physical Chemistry Göteborg University &RQVWUXFWLRQRIDSXOVHGG\HODVHU 3OHDVHREVHUYHWKDWWKHVDIHW\SUHFDXWLRQVRQSDJHPXVW EHIROORZHGRWKHUZLVHWKHUHLVDULVNRIH\HGDPDJH Renée Andersson -97,
More informationSpontaneous Emission, Stimulated Emission, and Absorption
Chapter Six Spontaneous Emission, Stimulated Emission, and Absorption In this chapter, we review the general principles governing absorption and emission of radiation by absorbers with quantized energy
More informationIntroduction to Spectroscopic methods
Introduction to Spectroscopic methods Spectroscopy: Study of interaction between light* and matter. Spectrometry: Implies a quantitative measurement of intensity. * More generally speaking electromagnetic
More informationTheory of optically thin emission line spectroscopy
Theory of optically thin emission line spectroscopy 1 Important definitions In general the spectrum of a source consists of a continuum and several line components. Processes which give raise to the continuous
More informationLaser Types Two main types depending on time operation Continuous Wave (CW) Pulsed operation Pulsed is easier, CW more useful
What Makes a Laser Light Amplification by Stimulated Emission of Radiation Main Requirements of the Laser Laser Gain Medium (provides the light amplification) Optical Resonator Cavity (greatly increase
More informationComments to Atkins: Physical chemistry, 7th edition.
Comments to Atkins: Physical chemistry, 7th edition. Chapter 16: p. 483, Eq. (16.1). The definition that the wave number is the inverse of the wave length should be used. That is much smarter. p. 483-484.
More informationNPTEL/IITM. Molecular Spectroscopy Lectures 1 & 2. Prof.K. Mangala Sunder Page 1 of 15. Topics. Part I : Introductory concepts Topics
Molecular Spectroscopy Lectures 1 & 2 Part I : Introductory concepts Topics Why spectroscopy? Introduction to electromagnetic radiation Interaction of radiation with matter What are spectra? Beer-Lambert
More information1. Transition dipole moment
1. Transition dipole moment You have measured absorption spectra of aqueous (n=1.33) solutions of two different chromophores (A and B). The concentrations of the solutions were the same. The absorption
More informationATOMIC AND LASER SPECTROSCOPY
ALAN CORNEY ATOMIC AND LASER SPECTROSCOPY CLARENDON PRESS OXFORD 1977 Contents 1. INTRODUCTION 1.1. Planck's radiation law. 1 1.2. The photoelectric effect 4 1.3. Early atomic spectroscopy 5 1.4. The postulates
More informationWhat are Lasers? Light Amplification by Stimulated Emission of Radiation LASER Light emitted at very narrow wavelength bands (monochromatic) Light
What are Lasers? What are Lasers? Light Amplification by Stimulated Emission of Radiation LASER Light emitted at very narrow wavelength bands (monochromatic) Light emitted in a directed beam Light is coherenent
More informationCHAPTER 3 RESULTS AND DISCUSSION
CHAPTER 3 RESULTS AND DISCUSSION 3.1 CHAPTER OUTLINE This chapter presents the data obtained from the investigation of each of the following possible explanations: (1) Experimental artifacts. (2) Direct
More informationPhotochemical principles
Chapter 1 Photochemical principles Dr. Suzan A. Khayyat 1 Photochemistry Photochemistry is concerned with the absorption, excitation and emission of photons by atoms, atomic ions, molecules, molecular
More informationElectron temperature is the temperature that describes, through Maxwell's law, the kinetic energy distribution of the free electrons.
10.3.1.1 Excitation and radiation of spectra 10.3.1.1.1 Plasmas A plasma of the type occurring in spectrochemical radiation sources may be described as a gas which is at least partly ionized and contains
More informationTeaching philosophy. learn it, know it! Learn it 5-times and you know it Read (& simple question) Lecture Problem set
Learn it 5-times and you know it Read (& simple question) Lecture Problem set Teaching philosophy Review/work-problems for Mid-term exam Review/re-work for Final exam Hand in homework every Monday (1 per
More informationIntroduction to scintillators
Introduction to scintillators M. Kobayashi (KEK) 17 November, 2003 1. Luminescence, fluorescence, scintillation, phosphorescence, etc. 2. Scintillation mechanism 3. Scintillation efficiency 4. Main characteristics
More informationFluorescence Quenching
Summary Fluorescence Quenching The emission of light from the excited state of a molecule (fluorescence or phosphorescence) can be quenched by interaction with another molecule. The stationary and time-dependent
More informationFluorescence polarisation, anisotropy FRAP
Fluorescence polarisation, anisotropy FRAP Reminder: fluorescence spectra Definitions! a. Emission sp. b. Excitation sp. Stokes-shift The difference (measured in nm) between the peak of the excitation
More information1. Strahlungsgesetze, Ableitung der Planck-schen Strahlungsformel, Einstein-Koeffizienten, Extinktinskoeffizient, Oszillatorenstärke
1. Strahlungsgesetze, Ableitung der Planck-schen Strahlungsformel, Einstein-Koeffizienten, Extinktinskoeffizient, Oszillatorenstärke Einheiten in diesem Kapitel: diesmal cgs. Energy volume density of blackbody
More informationChapter 2 Energy Transfer Review
Chapter 2 Energy Transfer Review In this chapter, we discuss the basic concepts of excitation energy transfer, making the distinction between radiative and nonradiative, and giving a brief overview on
More informationCollisional Excitation and N-Level Atoms.
Collisional Excitation and N-Level Atoms. 1 Collisional Excitation & Deexcitation Consider an atom or ion with a lower energy level 1 and an upper level. Collision of a free electron with kinetic energy
More informationPART VI : MOLECULAR LUMINESCENCE SPECTROSCOPY (Recommendations 1985)
PART VI : MOLECULAR LUMINESCENCE SPECTROSCOPY (Recommendations 1985) 1. INTRODUCTION This document does not aim to be completely self-contained since many of the terms and units needed for describing Molecular
More informationarxiv: v2 [physics.chem-ph] 8 Apr 2016
Rates and singlet/triplet ratios from TADF transients Mitchell C. Nelson (Dated: 15 March 2016) arxiv:1603.08998v2 [physics.chem-ph] 8 Apr 2016 Thermally activated delayed fluorescence has been reported
More informationWhat Makes a Laser Light Amplification by Stimulated Emission of Radiation Main Requirements of the Laser Laser Gain Medium (provides the light
What Makes a Laser Light Amplification by Stimulated Emission of Radiation Main Requirements of the Laser Laser Gain Medium (provides the light amplification) Optical Resonator Cavity (greatly increase
More informationHomework Due by 5PM September 20 (next class) Does everyone have a topic that has been approved by the faculty?
Howdy Folks. Homework Due by 5PM September 20 (next class) 5-Problems Every Week due 1 week later. Does everyone have a topic that has been approved by the faculty? Practice your presentation as I will
More informationLinear and nonlinear spectroscopy
Linear and nonlinear spectroscopy We ve seen that we can determine molecular frequencies and dephasing rates (for electronic, vibrational, or spin degrees of freedom) from frequency-domain or timedomain
More information24 Introduction to Spectrochemical Methods
24 Introduction to Spectrochemical Methods Spectroscopic method: based on measurement of the electromagnetic radiation produced or absorbed by analytes. electromagnetic radiation: include γ-ray, X-ray,
More information9. Transitions between Magnetic Levels Spin Transitions Between Spin States. Conservation of Spin Angular Momentum
9. Transitions between Magnetic Levels pin Transitions Between pin tates. Conservation of pin Angular Momentum From the magnetic energy diagram derived in the previous sections (Figures 14, 15 and 16),
More informationChapter-4 Stimulated emission devices LASERS
Semiconductor Laser Diodes Chapter-4 Stimulated emission devices LASERS The Road Ahead Lasers Basic Principles Applications Gas Lasers Semiconductor Lasers Semiconductor Lasers in Optical Networks Improvement
More informationOptical Spectroscopy. Steady State and Time Dependent Fluorescence Measurements. Kai Wen Teng. October 8 th PHYS 403 Fall 2013
Optical Spectroscopy Steady State and Time Dependent Fluorescence Measurements Kai Wen Teng October 8 th 2013 PHYS 403 Fall 2013 EM Spectrum of molecules Rotational Energy Infrared Vibrational Energy Near
More informationOptical and Photonic Glasses. Lecture 31. Rare Earth Doped Glasses I. Professor Rui Almeida
Optical and Photonic Glasses : Rare Earth Doped Glasses I Professor Rui Almeida International Materials Institute For New Functionality in Glass Lehigh University Rare-earth doped glasses The lanthanide
More information