ANALYSIS OF THE PERTURBATIONS IN THE $A^{1}\Pi$ STATE OF $^{13}C^{18}O$

Abstract

Author Institution: Department of physics and Physical Oceanography, Memorial University of Newfoundland; Department of physics and Physical Oceanography, Steacie Institute of Molecular Sciences; Department de Physique, Universit\'{e} de ToursThe vacuum ultraviolet spectrum of the fourth positive $(A^{1}\Pi-X^{1}\Sigma^{+})$ system of $^{13}C ^{18}O$ generated in emission in a jet discharge apparatus was photographed in the spectral region 1460-1670 {\AA} for the first time on a 10.6 m vacuum grating spectrograph. Detailed rotational analysis of nineteen bands involving seven vibrational levels ($v=0,1,2,4,6,7$, and 9) of the $A^{1}\Pi$ state was carried out. Several perturbations occurring in the $A^{1}\Pi$ state due to its neighbouring states $e^{3}\Sigma, a^{3} \Sigma^{+}, d^{3}\Delta_{i} I ^{1}\Sigma$ and $D^{1} \Delta$ were observed. The 1-0 band of the intercombination system $e^{3} \Sigma^{-} - X^{1} \Sigma^{\prime}$ was observed because of ``intensity borrowing” from the A-X system. From a deperturbation analysis, depertured molecular constants were obtained for the specified seven vibrational levels as well as for the perturbating states. Perturbation parameters and mixing coefficients which characterize the perturbations were also derived