The vapour phase Raman spectra, Raman band contour analyses, Coriolis coupling constants, and force constants for the molecules F¹²CH₃, F¹³CH₃, H¹²CCl₃and H¹³CCl₃

Abstract

The vapour phase Raman spectra of the molecules F12CHa, FlaCHa, H12CC13, and HlzCCla have been recorded at pressures of ca. 1 atmosphere over the fundamental frequency regions. Partly resolved rotational structure is reported for some fundamentals of methyl fluoride. The Raman band contours of the e-species fundamentals have been analysed to yield Coriolis constants from which e-species force constants have been calculated. The Coriolis and force constants so determined are compared with those based on analyses of appropriate vapour phase infra-red spectra.

High-Resolution Infrared Studies of ν1, 2ν1, and 2ν4 Bands of CH35Cl3

“…The J numbering was easily obtained by starting from the Q-branch edge. The assignment was confirmed with combination differences using the ground state rotational constants (5,9,10) quoted in Table 2. Around J = 20 small additional components can be observed on the highwavenumber side of the sharp peaks.…”

“…When including a Coriolis resonance with the component ν 2 + ν ±1 4 + 2ν ∓2 6 (E) a much better fit was obtained. The matrix element was [10] where F ± (J, k) = [J (J + 1) − k(k ± 1)] 1/2 . After some trials the parameters for the perturbers were fixed except ν 0 for ν 2 + ν ±1 4 + 2ν ±2 6 (A 1 + A 2 ).…”

Nuclear quadrupole coupling in chloroform and calibration of ab initio calculations

“…The value of the indeterminable rotational constant C for the parent was fixed at the value calculated from moments of inertia of the substituted isotopomer. The values for the quartic constant D K were fixed at estimates from a scaled ab inito calculation, carried out with the PC-GAMESS package [14,15], and were practically identical to those calculated from an experimental force field [16]. Complete tables of assigned transitions are deposited as Tables S1 and S2 of the electronic supplementary information, while selected strong hyperfine transitions for the parent species of chloroform are also listed in Table 1.…”