INVESTIGATING THE C-CL ANTIBONDING CHARACTER IN THE PI-PI-ASTERISK EXCITED-STATE OF VINYL, ALLYL, AND PROPARGYL CHLORIDE - EMISSION-SPECTRAAND AB-INITIO CALCULATIONS
Pw. Browning et al., INVESTIGATING THE C-CL ANTIBONDING CHARACTER IN THE PI-PI-ASTERISK EXCITED-STATE OF VINYL, ALLYL, AND PROPARGYL CHLORIDE - EMISSION-SPECTRAAND AB-INITIO CALCULATIONS, Journal of physical chemistry, 100(19), 1996, pp. 7765-7771
We report the emission spectra of dissociating vinyl, allyl, and propa
rgyl chloride upon photoexcitation at 199 nm. To provide a better unde
rstanding of the mixed electronic character in the Franck-Condon regio
n of the excited states accessed, we also present ab initio calculatio
ns at the configuration interaction level for these three molecules. T
hese experimental and theoretical results indicate large differences i
n the contribution of n sigma(C-Cl) and pi sigma*(C-Cl) character to
these predominantly pi pi(C=C/C=C) transitions. We present arguments
based on the symmetry of the pertinent molecular orbitals to explain t
his observed variation. We conclude by considering how the differing e
lectronic character of the excited state in these molecules may influe
nce the branching ratios to C-Cl fission and HCl elimination products
observed in the photodissociation of vinyl, allyl, and propargyl chlor
ide.