Emission spectroscopy of dissociative allyl iodide and allyl alcohol excited at 199.7 nm

We have investigated the emission spectroscopy of allyl iodide, CH2=CHCH2I, and allyl alcohol, CH2=CHCH2OH excited at 199.7 nm. Ab initio calculations at the configuration interaction with single excitation (CIS) level indica te that the excited state accessed near 200 nm in allyl iodide has mixed el ectronic character with contribution from a pi --> Rydberg(16) configuratio n, a pi (C=C)/n(1) --> sigma*(C-I)/pi*(C=C) configuration, and a pi --> Ryd berg(20) electronic configuration (where we have given the number of the Ry dberg molecular orbital in parentheses). The emission spectrum is dominated by activity in the CH2 wag and the C=C stretch, reflecting the dynamics of the molecule in the Franck-Condon region of the excited state. The emissio n spectrum along with the ab initio calculations on the two conformers of a llyl alcohol present at room temperature allow us to assign the transition at 200 nm to be mixed pi pi* character and pi --> Rydberg in character.