TY - JOUR
T1 - Caveats in the interpretation of time-resolved photoionization measurements
T2 - A photoelectron imaging study of pyrrole
AU - Crane, Stuart W.
AU - Zawadzki, Magdalena M.
AU - Thompson, James Oliver Frank
AU - Kotsina, Nikoleta
AU - Ghafur, Mohammed Omair
AU - Townsend, David
PY - 2016/12/21
Y1 - 2016/12/21
N2 - We report time-resolved photoelectron imaging studies of gas-phase pyrrole over the 267-240 nm excitation region, recorded in conjunction with a 300 nm probe. Of specific interest is the lowest-lying (3s/πσ) state, which exhibits very weak oscillator strength but is thought to be excited directly at wavelengths ≤254 nm. We conclude, however, that the only significant contribution to our photoelectron data at all wavelengths investigated is from non-resonant ionization. Our findings do not rule out (3s/πσ) state excitation (as appears to be confirmed by supporting time-resolved ion-yield measurements) but do potentially highlight important caveats regarding the use and interpretation of photoreactant ionization measurements to interrogate dynamical processes in systems exhibiting significant topological differences between the potential energy surfaces of the neutral and cation states.
AB - We report time-resolved photoelectron imaging studies of gas-phase pyrrole over the 267-240 nm excitation region, recorded in conjunction with a 300 nm probe. Of specific interest is the lowest-lying (3s/πσ) state, which exhibits very weak oscillator strength but is thought to be excited directly at wavelengths ≤254 nm. We conclude, however, that the only significant contribution to our photoelectron data at all wavelengths investigated is from non-resonant ionization. Our findings do not rule out (3s/πσ) state excitation (as appears to be confirmed by supporting time-resolved ion-yield measurements) but do potentially highlight important caveats regarding the use and interpretation of photoreactant ionization measurements to interrogate dynamical processes in systems exhibiting significant topological differences between the potential energy surfaces of the neutral and cation states.
UR - http://www.scopus.com/inward/record.url?scp=85006757996&partnerID=8YFLogxK
U2 - 10.1063/1.4972096
DO - 10.1063/1.4972096
M3 - Article
C2 - 28010111
AN - SCOPUS:85006757996
SN - 0021-9606
VL - 145
JO - The Journal of Chemical Physics
JF - The Journal of Chemical Physics
IS - 23
M1 - 234304
ER -