Ultrafast electron transfer studied by picosecond pulse radiolysis, new redox reactions. Mehran Mostafavi, April 2017, Vienna, Austria H 2 O * H 2 O

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1 Ultrafast electron transfer studied by picosecond pulse radiolysis, new redox reactions Mehran Mostafavi, April 2017, Vienna, Austria e hyd H 3 O + H 2 O * H 2 O H 2 O H 2 O + S e 1 Mostafavi, AIEA, April 2017, Vienne, Autriche ELYSE

2 Radiation Chemistry of Water Physical stage Physicochemical stage Chemical stage Buxton G.V An overview of the radiation chemistry of liquids. 2008,Radiation Chemistry Mostafavi, AIEA, April 2017, Vienne, Autrihe 2

3 Reactivity of e hyd and OH radicals H 2 O e ps H 2 O + H 2 O organic compounds S S?? S + H abstraction 1ps e hyd metal cations OH OH adduct biomolecules one e transfer inorganic anions G. V. Buxton et al. Critical review of rate constant for reactions of hydrated electron, hydrogen atom and hydroxyle radicals in aqueous solutions. J. Phy. Chem. Ref. Data. 1988, 17, 2. 10

4 Precursors Mostafavi, AIEA, Aril 2017, Vienne, Autrihe 8

5 Picosecond Pulse Radiolysis - ELYSE Pulse duration 7 15 ps Energy 8 MeV Charge 3 5 nc Frequency 5-20 Hz Porbe light: I I I I OD(, t) log log I I I I I réf dark réf dark sig dark sig dark cekove 20 nm Mostafavi, AIEA, April 2017, Vienne, Autrihe 5

6 e. Coupling of signal and reference into the optical fibres Pulse Probe setup Injection of 23 nm on the photocathode for electron pulse nm- 100 fs laser 2. Generation of the laser at 23 nm. Supercontinuum 7 5. Generation of probe at 23 nm 5 3. ns Delayline 11

7 Reactivity of H 2 O + in Neat Water H 2 O H 2 O + + e H 2 O + + H 2 O OH + H 3 O + 7 ps ELYSE 10 fs H 3 O + H 2 O + H 2 O OH e hyd 1 ps H 2 O e e Mostafavi, AIEA, April 2017, Vienne, Autrihe 7

8 Reactivity of H 2 O + in Solutions H 2 O H 2 O + + e H 2 O + + H 2 O OH + H 3 O + H 2 O + + S S + + H 2 O H 3 O + H 2 O + H 2 O? S OH e hyd S + 1 ps H 2 O e e Mostafavi, AIEA, April 2017, Vienne, Autrihe 8

9 Highly Concentrated H 2 SO Solutions H 2 O H 2 O + + e H 2 O + + H 2 O OH + H 3 O + OH + HSO SO + H 2 O Not possible on ps H 2 O + + SO 2 SO + H 2 O SO well known at 50 nm SO 2 SO + e 18 M H 2 SO the water molecule are rare After 7 ps electron pulse H 2 O + Formation of SO 9

10 10 3 x Absorbance / 5 mm Formation of SO in Solution H 2 SO 10 8 G (10-7 mol J -1 ) Concentration (mol / L) Yield of (SO ) Electron fraction (fs ) mol/l SO Mostafavi, AIEA, April 2017, Vienne, Autrihe (nm) 10

11 10 3 x Absorbance / 5 mm Formation of SO in Solution H 2 SO ps G (10-7 mol J -1 ) Concentration (mol / L) Electron fraction (fs ) mol/l Mostafavi, AIEA, April 2017, Vienne, Autrihe (nm) 11

12 10 3 x Absorbance / 5 mm Formation of SO in Solution H 2 SO 10 8 G (10-7 mol J -1 ) Concentration (mol / L) Electron fraction (fs ) mol / L Mostafavi, AIEA, April 2017, Vienne, Autrihe (nm) 12

13 10 3 x Absorbance / 5 mm Formation of SO in Solution H 2 SO 10 8 G (10-7 mol J -1 ) Concentration (mol / L) Electron fraction (fs ) mol/l Mostafavi, AIEA, April 2017, Vienne, Autrihe (nm) 13

14 10 3 x Absorbance / 5 mm Formation of SO in Solution H 2 SO G (10-7 mol J -1 ) Concentration (mol / L) Electron fraction (fs ) mol/l Mostafavi, AIEA, April 2017, Vienne, Autrihe (nm) 1

15 10 3 x Absorbance / 5 mm Formation of SO in Solution H 2 SO G (10-7 mol J -1 ) Concentration (mol / L) Electron fraction (fs ) mol/l Mostafavi, AIEA, April 2017, Vienne, Autrihe (nm) 15

16 10 3 x Absorbance / 5 mm Formation of SO in Solution H 2 SO G (10-7 mol J -1 ) Concentration (mol / L) Electron fraction (fs ) mol/l Mostafavi, AIEA, April 2017, Vienne, Autrihe (nm) 1

17 10 3 x Absorbance / 5 mm Formation of SO in Solution H 2 SO G (10-7 mol J -1 ) Concentration (mol / L) Electron fraction (fs ) mol/l Mostafavi, AIEA, April 2017, Vienne, Autrihe (nm) 17

18 10 3 x Absorbance / 5 mm Formation of SO in Solution H 2 SO G (10-7 mol J -1 ) Concentration (mol / L) Electron fraction (fs ) mol/l Mostafavi, AIEA, April 2017, Vienne, Autrihe (nm) 18

19 10 3 x Absorbance / 5 mm Formation of SO in Solution H 2 SO H 2 SO Neat G (10-7 mol J -1 ) Concentration (mol / L) Electron fraction (fs ) mol/l Mostafavi, AIEA, April 2017, Vienne, Autrihe (nm) 19

20 G (10-7 mol J -1 ) Formation of SO in Solution H 2 SO Concentration (mol / L) ps Electron fraction (fs ) Mostafavi, AIEA, April 2017, Vienne, Autrihe 19 H 2 SO Neat No H 2 O + 20

21 Formation of SO in Solution H 2 SO G (10-7 mol J -1 ) Concentration (mol / L) ps Electron fraction (fs ) Mostafavi, AIEA, April 2017, Vienne, Autrihe 21

22 Yield of sulfate radical x 10 7 mol J -1 Yield of SO radical Concentration (mol L -1 ) Oxidated Oxidaté by par Postive Hole Direct Effect H O + SO H O + SO SO SO SO e 2 SO 1 f fs Z H 2O Zwater f s 2 2 SO / w Electron fraction (f s ) G exp (SO ˉ) = f s G dir (SO 2ˉ) + f w G w (H 2 O +) G dir (SO 2ˉ) = mol J -1 from almost pure 18 M H 2 SO

23 E (Ox/Red) ENH H 2 O + /H 2 O HO + H + /H 2 O H 2 PO /H 2 PO - HSO /HSO - Potentiel redox mono-électronique 2.1 NO 3 /NO Cl /Cl Cl 2 /2Cl Br /Br HO /OH - Br 2 /2Br CO 3 - /CO 3 2- Mostafavi, AIEA, April 2017, Vienne, Autrihe 23

24 Ultrashort life time but ultraoxidizing Concentrated solutions Interface And corrosion Radiotherapy and radiobiology Mostafavi, AIEA, April 2017, Vienne, Autrihe 2

25 Absorbance / 0.5 cm Fuel retreatment in nitric acid solutions: NO 3 detection in 7 mol L -1 0, ,007 0,00 0,005 without contribution of empty cell empty cell with contribution of empty cell 02 nm 38 nm 7 nm 0,00 0,003 0,002 0,001 0,000 Mostafavi, AIEA, April 2017, Vienne, Autriche [nm] 25

26 Efficiency of hole trapping is concentration dependent. NO NO e 3 3 H O NO H O NO Mostafavi, AIEA, April 2017, Vienne, Autrihe 2

27 Corrosion at interface Low LET Radioactive Solid High LET Radioactive Solid 27

28 Dynamique de la solvatation de l électron e ps..e hyd Γ = 350 fs Vacuum p s hv Γ p = fast Γ IC ~ 50 fs Time-dependent absorption spectrum of electron in water from photon-ionizing of liquid water at 21 o C Γ s ~ 00 fs-1 ps Mostafavi, AIEA, April 2017, Vienne, Autrihe A. Migus. et al. Phys. Rev. Lett, 1987,

29 Reactivity of e ps in solutions H 2 O H 2 O + + e H 2 O + + H 2 O OH + H 3 O + H 2 O + + S S + + H 2 O e ps + X H + X -? H 2 O S + H 2 O + S S + Ag +? Ag e hyd 1 ps Ag 10 ps e hyd H 2 O e e ps Mostafavi, AIEA, April 2017, Vienne, Autrihe 29

30 Absorbance at 10 ps Ultrafast reduction of silver ion by prehydrated electron 0,10 e + Ag Ag - + 0,08 0,0 0,0 0,02 Absoprtion with two bands : hydrated electron and silver atom 0,00 Mostafavi, AIEA, April 2017, Vienne, Autrihe Wavelength Longueur d'onde (nm) 30

31 Absorbance/0.5 cm Strong scavenging of prehydrated electron nm neat water nm time (ps) time (ps) Mostafavi, AIEA, April 2017, Vienne, Autrihe 31

32 10 7 x G(Species) / mol J -1 Strong scavenging of prehydrated electron ,00 0,02 0,0 0,0 0,08 0,10 0,12 0,1 0,1 [AgClO ] / mol dm -3 Radiolytic yield of Ag and e aq as a function of AgClO concentration at 10 ps; G(Ag ) Experiment ( ), G(Ag ) Calculation ( ),G(e aq ) Experiment ( ), G(e aq ) Calculation ( ). Mostafavi, AIEA, April 2017, Vienne, Autrihe 32

33 Unexpected ultrafast silver ion reduction: dynamics Absorbance at 370 nm/0.5 cm G(Ag ) 7 ps X 10 7 mol J -1 driven by the solvent structure 0,1 1. M H 3 PO 0,1 0,12 neutral 0,10 10 M HClO Absorption due to Ag 0 observed at the end of 7 ps electron pulse 0,08 0,0 0,0 0,02 2,5 2,0 1,5 1,0 0,5 5.7 M HClO 0,00 0,0 0,00 0,02 0,0 0,0 0,08 Ag + mol L -1 0,00 0,05 0,10 0,15 0,20 Ag + mol L -1 Mostafavi, AIEA, April 2017, Vienne, Autrihe 33

34 Mostafavi, AIEA, April 2017, Vienne, Autrihe 3

35 Conclusion: Ultrafast redox reactions occurring under irradiation In parallel with proton transfer reaction, reactivity of H 2 O + in oxidation processes is clearly and quantitatively demonstrated. Usual Simulation Codes, do not take into account the oxidation reactivity of the radical cation of water. Maximum radiolytic yield of H 2 O + in H 2 SO is found to be.3 ± mol J -1. Prehydrated electron and the pair (e -, H + ) could reduced chemical species in less than 1 ps. 35 Mostafavi, AIEA, April 2017, Vienne, Autriche

36 Thanks for your attention! 3