Photoelectron Spectroscopy on HCl and DCl

1
Photoelectron Spectroscopy on HCl and DCl
Synchrotron Radiation Based Studies of
Dissociation Dynamics

• Florian Burmeister
• Department of Physics
• Uppsala University
• March 14, 2003

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Overview

• -Overview of Papers I-VI
• -The electronic structure of the molecule HCl
• -Papers I-III
• -Avoided crossing in the inner-valence band
• -Published spectra from MAX-lab
• -Recent results from BESSY and ALS

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Photoelectron spectroscopy
HCl
Energy relation hn EkinEB
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Bound and dissociative electronic states for
diatomic molecules
Potential energy
Ground state
Re
R
5
Papers I-IV
Potential energy (eV)
Ground state
0
Re
Internuclear distance H-Cl
6
Paper V
26
Final state
(4s)-1
Potential energy (eV)
Ground state
0
Re
Internuclear distance H-Cl
7
PaperVI
202
(2p)-1(6s)1
Excited state
Potential energy
Ground state
0
Re
Internuclear distance H-Cl
8
Valence-band spectroscopy on HCl
9
Potential curves in literature
40
M. Hiyama et al.CPL 210, 187 (1993)
35
Potential energy (eV)
30
25
Diabaticelectronicstates
20
1
2
3
4
5
Internuclear Distance H/D-Cl (Å)
10
A closer look on the inner-valence band 4s-1
for HCl and DCl
Direct photoionization using hn64eV BL I4-11 at
MAX-lab
F. Burmeister et al.PRA 65, 012704 (2001)
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A closer look on the inner-valence band 4s-1
for HCl and DCl
Direct photoionization using hn64eV BL I411 at
MAX-lab
Paper I
12
40
35
Theory
f2
Potential energy (eV)
30
Adiabatic electronic states
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1h
2h1p
f1
20
1
2
3
4
5
Distance H-Cl (Å)
13
Franck-Condon Projection in our case
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28
HCl
DCl
Binding energy (eV)
f2
Potential energy (eV)
26
26
1h
2h1p
f1
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F-C Region
1
2
3
4
5
Internuclear Distance H/D-Cl(Å)
14
Paper II
Intensity (arb. units)
Experimental broadening 30 meV
15
Theory Infinite resolution
DCl
HCl
Binding energy (eV)
16
Theory Infinite resolution
TCl
DCl
HCl
Binding energy (eV)
17
Theory Infinite resolution
TCl
DCl
HCl
1/2HCl
Binding energy (eV)
18
Theory Infinite resolution
TCl
DCl
HCl
1/2HCl
ee-Cl
Binding energy (eV)
19
Theory Infinite resolution
TCl
DCl
HCl
1/2HCl
ee-Cl
Binding energy (eV)
20
Theory Infinite resolution
Heisenberg relation
TCl
DCl
HCl
1/2HCl
ee-Cl
Binding energy (eV)
21
Reasons for coming to BESSY

• lower photon energy available at Bl U125/2
• less Doppler broadening better resolution
• collaboration provides Scienta with latest
• soft- and hardware
• correction of electron energy with time

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Paper III
DCl
BESSYExperimental broadening 10 meV
Binding energy (eV)
23
Paper III
DCl
BESSYExperimental broadening 10 meV
MAX-labExperimental broadening 30 meV
Binding energy (eV)
24
Paper III
DCl
HCl
ALSAndrew J. YenchaExperimental broadening
23 meV
Binding energy (eV)
25
Scientific context?

• - Couplings between electronic states of
  fundamental importance for Chemistry
• Chemical Reactions
• - Physics In our field the dynamial couplings
  have typically been neglected for the
  understanding of photoelectron spectra
• - This project approaches Physics to Chemistry

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Conclusions

• - Paper I In the case of HCl, a dynamic
  coupling between two adiabatic electronic states
  were observed for moderate resolution
• - Paper II Theory predicted the appearance of
  vibrational bands for DCl for improved
  resolution
• - Paper III Experimental confirmation of
  theoretical prediction