VIBRATIONAL QUANTUM GRAPHS AND THEIR APPLICATION TO THE QUANTUM DYNAMICS OF CH5+
Csaba Fábri, Attila Géza Császár · Proceedings of the 73rd International Symposium on Molecular Spectroscopy · 2018
Only old IR and no MW data exist for this molecule.\\footnote{Friedman \\& Turkevich, J. Chem. Phys. \\textbf{17}, 1012 ff. (1949); McMurry, Thornton \\& Condon, J. Chem. Phys. \\textbf{17}, 918 ff. (1949); McMurry \\& Thornton, J. Chem. Phys. \\textbf{19}, 1014 ff. (1951).; Gayles \\& King, Spectrochim. Acta \\textbf{21}, 543 ff. (1965); Kondo \\& Saeki, Spectrochim. Acta \\textbf{29A}, 735 ff. (1973).} Last year we reported (2017 ISMS, TK08) on the \ ub{20} (B$_{1}$) A-type band recorded in CLS Cycle 23 (Jan-May, 2016). This was the only band with easily assignable lines. Other bands were perturbed and not assignable at present. We assigned most of \ ub{20} and rotational constants were determined for this molecule. Our \ ub{20} data was limited in K and J values due to the pressure used and time limitations in that cycle. Also some small torsional perturbations may have affected the derived constants. From our recent studies \ ub{9} bands appear unperturbed for the other $^{13}$C and D isotopologues. Therefore we recorded that band for 2,2-D$_{2}$-Propane in the Far-IR at higher pressures in new experiments. The spectrum of the \ ub{9} (A$_{1}$) band (CCC bend) was recorded on the Far-IR beamline during CLS Cycle 27 (Jun-Dec, 2017). Spectra were recorded at 4.055 Torr ($\\Delta$$\ u$ = 0.00096 cm-1) and 7.691 Torr ($\\Delta$$\ u$ = 0.0020 cm-1) to see higher K and J transitions. An optical path of 72 m and a cell temperature of 265.75K were used. We assigned over 5900 lines with both traditional methods and the aid of the PGOPHER program of Colin Western.\\footnote{C. Western, JQSRT \\textbf{186}, 221 ff. (2017)} Lines up to K = 37 and J = 55 were assigned by using both pressure data sets. Improved rotational constants including the inertial and centrifugal distortional constants will be reported. This varied isotopic data should improve the r$_{0}$ structure.