Rydberg atoms. Tobias Thiele

Transcription

1 Rydberg atoms Tobias Thiee

2 References T. Gaagher: Rydberg atoms Content Part : Rydberg atoms Part : A typica beam experiment

3 Introduction hat is Rydberg? Rydberg atoms are (any) atoms in state with high principa quantum number n.

4 Introduction hat is Rydberg? Rydberg atoms are (any) atoms in state with high principa quantum number n. Rydberg atoms are (any) atoms with exaggerated properties

5 Introduction hat is Rydberg? Rydberg atoms are (any) atoms in state with high principa quantum number n. Rydberg atoms are (any) atoms with exaggerated properties equivaent!

6 Introduction How was it found? In 885: Bamer series: Visibe absorption waveengths of H: bn n Other series discovered by Lyman, Brackett, Paschen,... Summarized by Johannes Rydberg:

7 Introduction How was it found? In 885: Bamer series: Visibe absorption waveengths of H: bn n Other series discovered by Lyman, Brackett, Paschen,... Summarized by Johannes Rydberg:

8 Introduction How was it found? In 885: Bamer series: Visibe absorption waveengths of H: bn n Other series discovered by Lyman, Brackett, Paschen,... Summarized by Johannes Rydberg: ~ ~ Ry n

9 Introduction Generaization In 885: Bamer series: Visibe absorption waveengths of H: bn n Other series discovered by Lyman, Brackett, Paschen,... Quantum Defect was found for other atoms: ~ ~ Ry ( n )

10 Introduction Rydberg formua? Energy foows Rydberg formua: E E hry ( n )

11 Introduction Rydberg formua? Energy foows Rydberg formua: E hry 3.6 ev E ( n )

12 Energy Introduction Hydrogen? 0 Energy foows Rydberg formua: E 0 hry hry E ( n ) n ev

13 Energy Quantum Defect? 0 Energy foows Rydberg formua: E E Quantum Defect hry ( n )

14 Rydberg Atom Theory Rydberg Atom A e Amost ike Hydrogen Core with one positive charge One eectron hat is the difference?

15 Rydberg Atom Theory Rydberg Atom A e Amost ike Hydrogen Core with one positive charge One eectron hat is the difference?

16 Rydberg Atom Theory Rydberg Atom A e Amost ike Hydrogen Core with one positive charge One eectron hat is the difference?

17 Rydberg Atom Theory Rydberg Atom A e Amost ike Hydrogen Core with one positive charge One eectron hat is the difference? No difference in anguar momentum states

18 Radia parts-interesting regions V ( r) r 0 r

19 Radia parts-interesting regions 0 V ( r) Vcore( r) r V ( r) r r

20 Radia parts-interesting regions r r 0 Ion core 0 V ( r) Vcore( r) r V ( r) r r

21 Radia parts-interesting regions r r 0 Ion core 0 V ( r) Vcore( r) r V ( r) r r Interesting Region For Rydberg Atoms

22 Radia parts-interesting regions r r 0 Ion core 0 V ( r) Vcore( r) r V ( r) r r H

23 Radia parts-interesting regions r r 0 Ion core 0 V ( r) Vcore( r) r V ( r) r r H nh

24 Radia parts-interesting regions r r 0 Ion core 0 V ( r) Vcore( r) r V ( r) r r δ H nh

25 (Heium) Energy Structure ( n ) usuay measured Ony arge for ow (s,p,d,f) He eve structure is big for s,p

26 (Heium) Energy Structure ( n ) usuay measured Ony arge for ow (s,p,d,f) He eve structure is big for s,p

27 (Heium) Energy Structure ( n ) usuay measured Ony arge for ow (s,p,d,f) He eve structure is big for s,p

28 (Heium) Energy Structure ( n ) usuay measured Ony arge for ow (s,p,d,f) He eve structure is big for s,p Excentric orbits penetrate into core. Large deviation from Couomb. Large phase shift-> arge quantum defect

29 (Heium) Energy Structure ( n ) usuay measured Ony arge for ow (s,p,d,f) He eve structure is big for s,p d dn ( n ) 3

30 Eectric Dipoe Moment Eectron most of the time far away from core Strong eectric dipoe: Proportiona to transition matrix eement ( n ) d dn ( n ) 3

31 Eectric Dipoe Moment Eectron most of the time far away from core Strong eectric dipoe: d er Proportiona to transition matrix eement ( n ) d dn ( n ) 3

32 Eectric Dipoe Moment Eectron most of the time far away from core Strong eectric dipoe: d er Proportiona to transition matrix eement d e r e r cos() f i f i f i ( n ) d dn ( n ) 3

33 Eectric Dipoe Moment Eectron most of the time far away from core Strong eectric dipoe: Proportiona to transition matrix eement d e r e r cos() e find eectric Dipoe Moment f f Cross Section: i d i r f i d er cos( ) n f i ( n ) d dn ( n ) 3 d a 0 n

34 Eectric Dipoe Moment Eectron most of the time far away from core Strong eectric dipoe: Proportiona to transition matrix eement d e r e r cos() e find eectric Dipoe Moment f f Cross Section: i d i r f i d er cos( ) n r n f i ( n ) d dn ( n ) 3 d a 0 n n

35 Stark Effect H H df E 0 For non-hydrogenic Atom (e.g. Heium) Exact soution by numeric diagonaization of f H i f H0 i f d i F in undisturbed (standard) basis ( n ~,,m) ( n ) d dn ( n ) 3 d a 0 n n

36 Stark Effect H H df E For non-hydrogenic Atom (e.g. Heium) Exact soution by numeric diagonaization of f H i f H0 i f d i F in undisturbed (standard) basis ( n ~,,m) 0 ( n ) ( n ) d dn ( n ) 3 d a 0 n n

37 Stark Effect H H df E For non-hydrogenic Atom (e.g. Heium) Exact soution by numeric diagonaization of f H i f H0 i f d i F in undisturbed (standard) basis ( n ~,,m) 0 ( n ) Numerov ( n ) d dn ( n ) 3 d a 0 n n

38 Stark Map Hydrogen n=3 n= n=

39 Stark Map Hydrogen n=3 Leves degenerate n= n=

40 Stark Map Hydrogen n=3 k=- bue n= k= red n=

41 Stark Map Hydrogen n=3 Leves degenerate n= Cross perfect Runge-Lenz vector conserved n=

42 Stark Map Heium n=3 n= n=

43 Stark Map Heium n=3 Leves not degenerate n= n=

44 Stark Map Heium n=3 k=- bue n= k= red n=

45 Stark Map Heium n=3 k=- bue n= s-type k= red n=

46 Stark Map Heium n=3 Leves degenerate n= Do not cross! No couomb-potentia n=

47 Ingis-Teer Limit n -5 Stark Map Heium n=3 n= n=

48 Hydrogen Atom in an eectric Fied Rydberg Atoms very sensitive to eectric fieds Sove: H H df E in paraboic coordinates 0 Energy-Fied dependence: Perturbation-Theory n 5 n 3 F F( n n ) n n 6 k 7n 9m 9 O( ) 3( n n ) k

49 Hydrogen Atom in an eectric Fied hen do Rydberg atoms ionize? No fied appied Eectric Fied appied Cassica ionization: Vaid ony for Non-H atoms if F is Increased sowy ( n ) d dn ( n ) 3 d a 0 n n 5 F IT n

50 Hydrogen Atom in an eectric Fied hen do Rydberg atoms ionize? No fied appied Eectric Fied appied Cassica ionization: Vaid ony for Non-H atoms if F is Increased sowy ( n ) d dn ( n ) 3 d a 0 n n 5 F IT n

51 Hydrogen Atom in an eectric Fied hen do Rydberg atoms ionize? No fied appied Eectric Fied appied Cassica ionization: V Fz r Fc 6n Vaid ony for Non-H atoms if F is Increased sowy F c 6n ( n ) d dn ( n ) 3 d a 0 n n 5 F IT n F c n 6

52 Hydrogen Atom in an eectric Fied hen do Rydberg atoms ionize? No fied appied Eectric Fied appied Cassica ionization: V Fz r Fc 6n Vaid ony for Non-H atoms if F is Increased sowy F c 6n ( n ) d dn ( n ) 3 d a 0 n n 5 F IT n F c n 6

53 Hydrogen Atom in an eectric Fied hen do Rydberg atoms ionize? No fied appied Eectric Fied appied Quasi-Cassica ioniz.: Z V ( ) m0 F Z m F F c 6n ( n ) d dn ( n ) 3 d a 0 n n 5 F IT n F c n 6

54 Hydrogen Atom in an eectric Fied hen do Rydberg atoms ionize? No fied appied Eectric Fied appied Quasi-Cassica ioniz.: Z V ( ) m0 F Z 9n m red F F c 6n F r 9n ( n ) d dn ( n ) 3 d a 0 n n 5 F IT n F c n 6

55 Hydrogen Atom in an eectric Fied hen do Rydberg atoms ionize? No fied appied Eectric Fied appied F b 9n Quasi-Cassica ioniz.: F c 6n V ( ) F Z Z m F red 9n bue 9n F r 9n ( n ) d dn ( n ) 3 d a 0 n n 5 F IT n F c n 6

56 Hydrogen Atom in an eectric Fied Bue states Ingis-Teer cassic Red states

57 Lifetime From Fermis goden rue Einstein A coefficient for two states A n,, n, e 3c 3 n,, n, 3 max(, ) n r n n, n, Lifetime ( n ) d dn ( n ) 3 d a 0 n n 5 F IT n F c n 6

58 Lifetime From Fermis goden rue Einstein A coefficient for two states A n,, n, e 3c 3 n,, n, 3 max(, ) n r n n, n, Lifetime, n A n, n, n,, n, ( n ) d dn ( n ) 3 d a 0 n n 5 F IT n F c n 6

59 Lifetime From Fermis goden rue Einstein A coefficient for two states A n,, n, e 3c 3 n,, n, 3 max(, ) n r n n, n, Lifetime, n A n, n, n,, n, ( n ) d dn ( n ) 3 d a 0 n n 5 F IT n F c n 6

60 Lifetime From Fermis goden rue Einstein A coefficient for two states A n,, n, e 3c 3 n,, n, 3 max(, ) n r n n, n, Lifetime, n A n, n, n,, n, 3 For 0: n Overap of F ( n ) d dn ( n ) 3 d a 0 n n 5 F IT n F c n 6 3, 0 n n

61 Lifetime From Fermis goden rue Einstein A coefficient for two states A n,, n, e 3c 3 n,, n, 3 max(, ) n r n n, n, Lifetime, n A n, n, n,, n, For n: n Overap of F 3 For n: n Overap of F ( n ) d dn ( n ) 3 d a 0 n n 5 F IT n F c n 6 3 n, n,n 5

62 Lifetime A n,, n, e 3c 3 n,, n, 3 max(, ) n r n, n A n, n, n,, n, State Stark State 60 p ( n,) sma Circuar state 60 =59 m=59 ( n, ) ( n, ) Statistica mixture Scaing 3 n (overap of n 3 ) n 5 r n.5 n Lifetime 7. ms 70 ms ms ( n ) d dn ( n ) 3 d a 0 n n 5 F n F c n 3 5 IT n, n, n 6

63 Part - Generation of Rydberg atoms Typica Experiments: Beam experiments (utra) cod atoms Vapor ces

64 ETH physics Rydberg experiment Creation of a cod supersonic beam of Heium. Speed: 700m/s, pused: 5Hz, temperature atoms=00mk

65 ETH physics Rydberg experiment Excite eectrons to the s-state, (to overcome very strong binding energy in the xuv range) by means of a discharge ike a ightning.

66 ETH physics Rydberg experiment Actua experiment consists of 5 eectrodes. Between the first the atoms get excited to Rydberg states up to n=inf with a dye aser.

67 Dye/Yag aser system

68 Dye/Yag aser system Experiment

69 Dye/Yag aser system Experiment Nd:Yag aser (600 mj/pp, 0 ns puse ength, Power -> 0ns of M!!) Provides energy for dye aser

70 Dye/Yag aser system Dye aser with DCM dye: Dye is excited by Yag and fuoresces. A cavity creates ight with 6 nm waveength. This is then frequency doubed to 3 nm. Experiment Nd:Yag aser (600 mj/pp, 0 ns puse ength, Power -> 0ns of M!!) Provides energy for dye aser

71 Dye aser Nd:Yag pump aser cuvette Frequency doubing DCM dye

72 ETH physics Rydberg experiment Detection:. kv/cm eectric fied appied in 0 ns. Rydberg atoms ionize and eectrons are Detected at the MCP detector (singe partice mutipier).

73 Resuts TOF 00ns

74 Resuts TOF 00ns Ingis-Teer imit

75 Resuts TOF 00ns Adiabatic Ionizationrate ~ 70% (fitted) n d 50V cm 6 F 0

76 Resuts TOF 00ns Adiabatic Ionization- Pure diabatic Ionizationrate ~ 70% (fitted) rate: exp( t) n d 50V cm 6 F 0 n d 50V 9 cm F0

77 Adiabatic Ionizationrate ~ 70% (fitted) Resuts TOF 00ns 3 Pure diabatic Ionizationrate: exp( t) saturation r n From ground state n d 50V cm 6 F 0 n d 50V 9 cm F0

78 Resuts TOF 5ms r 3 n From ground state ifetime n 3 n d 50V cm 6 F 0 n d 50V 9 cm F0