UV ABSORPTION SPECTRA OF CH2,CD2CH_{2}, CD_{2}, AND CHO FROM AB INIO POTENTIAL. ENERGY SURFACES AND A WAVEPACKET TREATMENT

$^{1.}$ R.A. Bearda, M.C. van Hemert and E.F. van Dishoeck, J. Chem, Phys. 97,8240 (1992).Author Institution: Department of Chemistry, Gorlaeus Laboratories, Leiden University; Sterrewacht Leiden, Leiden UniversityFull 3-D ab initio potential energy suitaces for the ground state of $CH_{2}, X ^{2}B, / X ^{3}A^{\prime\prime}$. and for a large number of excited states as well as transition dipole moment functions, were calculated recently'. The surfaces and transition dipole moments were used subsequently in wave packet studies of the dynamics of the nuclei in the excited states. Absolute photodissociation cross sections, $\sigma(\lambda)$ have been obtained for the lowest two excited states, $1^{3}A$ and $2^{3}A^{\prime}$. The associated absorption spectra were compared with literature data. Rotational and vbrational ditrbutions of the fragments have been obtained also. The eflect of isotope substitution was investigated and the applicablity of simplitications in the dynamics treatment, e.g. 2-D studies and the rolational Franck Condon approximation, was analysed