The &#946;- and &#947;-band systems of <SUP>14</SUP>NS and <SUP>15</SUP>NS

The spectra of 14NS and 15NS molecules are obtained in a 2450 mc./s. microwave oscillator discharge. Vibrational assignments of the &#946;- and &#947;-systems are studied in more detail. Several hitherto unrecorded bands are satisfactorily explained as belonging to higher v', v" levels in the Deslandres schemes of both &#946;- and &#947;-systems. The observed isotope shifts (14NS-15NS) provide confirmatory evidence for the proposed vibrational analysis. In the case of the &#947;-system, the v'=2 level of the upper state appears to be strongly perturbed showing a shift of about 38 cm.&#8722;1 from the expected position. In the &#946;-system, the isotopic shifts in the band-heads involving the v'=0 and 1 levels of the 2&#916;5/2 of the upper state show small deviations from expected values. The reality of these small deviations is established beyond doubt by the occurrence of the effect on the 0–0 sub-band which exhibits the isotopic head in a wavelength direction opposite to the expected one

A new <SUP>2</SUP>&#928;-X<SUP>2</SUP>&#928; band system of NS

Vibrational and rotational analysis of some bands forming a new band system of NS is given. It is also shown that the system involves the ground X2&#928; reg. state of the molecule, and is due to the transition 2 &#928;reg.&#8594;X2&#928;reg. The bands form a single v"=0 progression with v'=7, 8, 9 and 10. The assignment of these quantum numbers v', v" is supported by (1) &#916;2F" (J) values which are identical with those for the v"=0 bands of the &#946; and &#947; systems and (2) the isotopic shift data from 15NS bands, respectively

ANALYSIS OF THE 3900 {\AA} ABSORPTION SYSTEM (V SYSTEM) OF CARBON DISELENIDE

$^{1}$G. W. King and K. Srikameswaran, J. Mol. Spectrosc. 31, 296 (1969).Author Institution: Department of Chemistry, University of Western Ontario London; Department of Chemistry, McMaster University HamiltonUnlike vibronic bands of the $\tilde{a} B_{2}(^{3}A_{2})\leftarrow\tilde{X} ^{1}A_{1}$ $system^{1}$, those of the higher energy $(\lambda\lambda$ 4050 - 3450 {\AA}) V system appear to have a complex rotational structure. Those at the violet end of the region are probably as difficult to analyse as those of the analogous system in $CS_{2}$: while those at the red end are distinctly violet degraded, but still complex. Analysis of the vibrational structure indicates that long progressions in the bending mode $(\nu_{2}{^{\prime\prime}})$ are not well developed, whereas progressions in the symmetric stretching mode $(\nu_{1})$ are indeed evident. Some possible explanations of our observations are presented here along with the available data on the spectra of the system obtained from both $CSe_{2}^{80}$ and $CSe_{2}^{78}$ molecules

ROTATIONAL ANALYSIS OF BANDS IN THE 2348 {\AA} SYSTEM OF SO2SO_{2}

$^{1}$ J. B. Coon and P. Tsao, XXVI Symp. Mo1. Struct., Columbus, Ohio, 1971. $^{2}$ I. Dubois, J. Mo1. Struct. 3, 269 (1969)""Author Institution: Department of Chemistry, University of western Ontario LondonSeveral bands of the 2350 {\AA} system of sulfur dioxide have been rotationally analyzed. These bands are type A transitions of an asymmetric rotor; thus the electronic transition is $^{e}B_{2} \leftarrow ^{e}A_{1}$, identified with the $\Pi^{*} \leftarrow \Pi$ one-electron promotion $2b_{1} \leftarrow 1a_{2}$. The present results support the vibrational analysis given by Coon and $Tsao^{1}$, but are not in agreement with the partial rotational analyses given by $Dubois^{2}$ or with the suggestion that overlapping band systems are present in this region. Constants for two low-energy transitions in the system are given below (in $cm^{-1}$). Results for other transitions will be discussed.\\ \def \a {\hphantom {$_{K}$}} \def \b {\hphantom {$_{J}$}} \begin{tabular}{lllll} \hline $\nu_{000}$ &42573.30 &$A_{000}$ $1.151_{2}$ &$10^{5}D_{J}$ \a$0.02_{8}$ &$\Delta_{000}$ $0.16$ amu {\AA}$^{2}$ \\ &&$B_{000}$ $0.347_{3}$ &$10^{5}D_{JK}$ $1.6_{1}$ \\ & &$C_{000}$ $0.266_{1}$ &$10^{5}D_{K}$ \b $0.9_{1}$ &\\ &&&&\\ $\nu_{000}$ &42950.88 &$A_{010}$ $1.171_{4}$ &$10^{5}D_{J}$ \a $0.02_{5}$ &$\Delta_{010}$ $0.30$ \\ &&$B_{010}$ $0.345_{9}$ &$10^{5}D_{JK}$ $1.6_{1}$ \\ & &$C_{010}$ $0.265_{8}$ &$10^{5}D_{K}$ \b $1.1_{5}$ &\\ \hline \end{tabular