Precise ground state molecular parameters of chloromethane

Rotational spectrum of 13C chloromethanes

“…It is appropriate to mutually compare the chlorine quadrupole constants determined for the 12 and 13 isotopologues. In our recent study [6] on the 12 methyl chloride, we derived eQq 0 = À74.7631 (35) and À58.9096 (26) MHz for the 35 and 37 isotope, respectively, and the very good agreement between the quadrupole constants of the same chlorine nuclei can be seen comparing with the values in Tables 1 and 2. This agreement is a consequence of the Born-Oppenheimer theoretical presumptions, which assume the uniform molecular geometry and gradient of electrostatic potential (electron density).…”

“…The optical path length of a conventional glass 280 cm long cell was doubled using a roof top mirror and a polarization grid as described in [6,7]. The sample pressures were measured by a capacitance gauge from Leybold with relative uncertainty about 5%.…”

“…Finally this discussion is negatively influenced by lower accuracies of the spin-rotational constants (compare the 12 carbon isotopologue C N values determined as 0.00256 (12) and 0.00173 (24) for 12 CH 3 35 Cl and 12 CH 3 37 Cl, respectively, see Ref. [6], with those in Tables 1 and 2) that are probably not sufficient enough for a clear evaluation. …”

Rotational spectra of hydrazoic acid

“…The measurements were made in the frequency range between 90 and 672 GHz with the Prague semiconductor millimetre-wave high resolution spectrometer. This spectrometer was described in previous papers [6][7][8]. Frequency modulation was used with the second harmonic lock-in detection.…”

Line-mixing between rotational Stark components of CH3F self-perturbed and perturbed by helium: Experimental results and IOS analysis

“…1) and the semiconductor millimeter wave high resolution spectrometer [19,20] at ICT in Prague. The microwave radiation is synthesized using a swept signal generator 83650 B (Agilent) operating from 10 MHz to 50 GHz.…”