Premium
Velocity Mapping Studies of Vibrational Energy Disposal Following Methyl Iodide Photodissociation
Author(s) -
Parker David H.,
Kitsopolous Theofanis
Publication year - 1999
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.199900069
Subject(s) - chemistry , photodissociation , methyl iodide , excited state , dissociation (chemistry) , resonance enhanced multiphoton ionization , atomic physics , ionization , methyl radical , photoelectric effect , excitation , mass spectrometry , radical , iodide , bond dissociation energy , ab initio , photochemistry , photoionization , optics , physics , ion , organic chemistry , quantum mechanics , chromatography , medicinal chemistry
In this paper previous results are compared for two different types of velocity mapping studies which probe vibrational energy disposal following the A‐band photodissociation of methyl iodide, CH 3 I + hv → CH 3 (v) + 1( 2 P 3/2 ), 1*( 2 P 1/2 ). Full three‐dimensional state‐specific speed and angular distributions of the nascent fragments have been recorded for the photoelectrons, iodine atoms, and methyl radicals, using state‐ and mass‐selective (2+1) resonance‐enhanced multi‐photon ionization (REMPI)/time‐of‐flight spectrometry. Two sources of information on the vibrational energy disposal are available from velocity mapping: (a) the photoelectron images, which give information on the initial stages of vibrational excitation in electronically excited CH 3 I, and (b) methyl radical images, which indicate the final energy disposal channels. Even though the two signals are believed to probe very different time‐scales of the dissociation process, good agreement between the two is found for the vibrational energy disposal trends. Several trends found in the data for methyl iodide photodissociation indicate that readjustment of the ab initio multi‐dimensional potential energy surfaces calculated for this molecule appears to be needed.