STIMULATED EMISSION PUMPING SPECTROSCOPY OF THE FIRST EXCITED SINGLET STATE OF GERMYLIDENE $(H_{2}C=Ge)$

Author Institution: Department of Chemistry, University of KentuckyThe $\tilde{A}^{1} A_{2}$ States of $H_{2}CGe$ and $D_{2}CGe$ have been explored for the first time by $\tilde{A} - \tilde{X}$ laser-induced fluorescence (LIF) spectroscopy of the orbitally forbidden $S_{1} - S_{0}$ transition and stimulated emission pumping (SEP) and wavelength resolved fluorescence studies of the allowed $\tilde{B} - \tilde{A}$ electronic transition. Medium-resolution SEP studies gave the excited $\tilde{A}$ state $\nu_{2}, \nu_{3}, \nu_{4}$, and $\nu_{6}$ vibrational frequencies for $H_{2}C^{74}Ge$ and $D_{2}C^{74} Ge$. The $4^{1}$ and $6^{1}$ levels and higher combination and overtone states are strongly Coriolis coupled, which perturbs the rotational subband structure, limiting the accuracy of the determination of the vibrational frequencies. High-resolution SEP studies of the $\tilde{B} - \tilde{A} 0^{0}_{0}$ band have allowed us to determine the rotational constants of the $\tilde{A}$ state of $H_{2}C^{74}Ge$, from which we were able to calculate an approximate $r_{0}$ structure with the CH bond length constrained to the ground state value. The zero-point level of $D_{2}C^{74}Ge$ is substantially perturbed, most plausibly by interaction with an excited vibrational level of the nearby triplet ($\tilde{a}^{3} A_{2}$) state