Mj. Dewitt et Rj. Levis, THE ROLE OF ELECTRON DELOCALIZATION IN THE IONIZATION OF C-6 HYDROCARBONS USING INTENSE 780 NM LASER-PULSES OF FEMTOSECOND DURATION, The Journal of chemical physics, 108(17), 1998, pp. 7045-7048
The photoionization/dissociation mass spectra are reported for the ser
ies of molecules benzene (C6H6), 1,3,5-hexatriene (C6H8), cyclohexane
(C6H12), and n-hexane (C6H14) as a function of laser power intensity f
rom 1 to 3.8 x 10(13) W cm(-2) using a pulse duration of 170 fs and wa
velength 780 nm. The ionization orders are localized around 8.3 for be
nzene, 1,3,5-hexatriene, and cyclohexane and the relative ionization p
robabilities are measured to be 1,79, and 0.15, respectively. No ion c
urrent was observed for n-hexane. The dissociation yield is observed t
o increase exponentially as a function of the number of atoms in the m
olecule with cyclohexane undergoing the most dissociation and benzene
undergoing essentially no dissociation. These observations are interpr
eted in light of a field ionization model that incorporates both the i
onization potential and the electronic and nuclear structure of the mo
lecule. (C) 1998 American Institute of Physics.