ANALYSIS OF THE HIGH-RESOLUTION INFRARED SPECTRUM OF METHYL ISOCYANIDE

$^{1.}$ A. Bauer, M. Bogey, and M. A. Kastler, C. R. Acad. Sci. Ser. B 271. 892 (1970). $^{2.}$ A. Bauer, M. Bogey, and S. Maes, J. Phys. (Paris) 32, 763(1971). $^{3.}$ J. Pliva, personal communication.Author Institution: Department of Chemistry 152 Davey Laboratory, The Pennsylvania State UniversityThe infrared spectrum of methyl isocyanide, CH3NC, has been measured in the region $2120-2190 cm^{-1}$ at a resolution of $0.002 cm^{-1}$ using a Bomem $DA_{3}$ Fourier-transform spectrometer. The $\nu_{2}$ fundamental band and two combination band. $\nu_{2}+\nu_{8}-\nu_{8}$ and $\nu_{2}+2\nu_{8}-2\nu_{8}$, have been assigned. Molecular constants for the upper states of the three bands have been derived using the ground state constants determined by microwave $spectroscopy^{1.2}$ and fitting procedures and programs developed by $Plfva^{3}$

6Li−7Li^{6}Li-^{7}Li ISOTOPE EFFECTS IN THE A1Σu+−X1Σg+A^{1}\Sigma_{u}{^{+}}-X^{1}\Sigma_{g}{^{+}} BAND SYSTEM OF Li2Li_{2}

Author Institution: Department of Chemistry, The Pennsylvania State UniversityThe absorption spectrum of the A-X band system of $^{6}Li_{2}$ has been examined using a Bomem DA3.002 Fourier Transform Interferometer in the frequency range of $14200-17200 cm^{-1}$. A high resolution $(0.01 cm^{-1}$) spectrum was measured at two different temperatures (600 and $830^{\circ}C$) in a heat pipe overn containing helium as a buffer gas. The spectrum was analyzed to yield Dunham coefficients and Franck-Condon factors. The molecular constants calculated for $^{6}Li_{2}$ are compared with those for $^{7}Li_{2}$

ROVIBRATIONAL ANALYSIS OF THE CH STRETCHING OF METHYL ISOCYANIDE

Author Institution: Department of Chemistry, Penn State University; Department of Physics, Penn state UniversityThe symmetric stretching of the methyl group ($v_{1}$) of $CH_{3}NC$ has been recorded using a Fourier Transform Spectrometer with an unapodized resolution of $0.004 cm^{-1}$. The rotational structure has been revealed for the first time, and the molecular constants have been obtained. Over 400 spectral lines have been assigned to the P- and R-transitions of this parallel band with $K = 0$ to $K=6$ and $J = 40$. The rotational structure of the $v_{1}$ is quite different from a typical parallel band (e.g., $v_{4}$ of $CH_{3}NC$ because of the small $\Delta$(B) and large $\Delta$(A-B) values, giving rise to an intermingling of spectral lines belonging to different J-multiplets. In addition, all of the K-subbands have been observed to he strongly perturbed. The structure analysis, spectral assignment, and perturbation origin will be discussed in this presentation."