The halfwidths of CO vibration–rotation lines, pressure-broadened by N2 have been measured in the fundamental band at −83, −148, and −180 °C, using a variable temperature absorption cell and a high resolution spectrometer. The temperature dependence of linewidths has been calculated from the Anderson–Tsao–Curnutte theory and compared to the experimental determinations.
Foreign gas broadening and shift of the vibration-rotation lines in the fundamental band of hydrogen fluoride have been investigated. Using mathematical modeling of measuring the absorption of radiation of an electric discharge HF laser, the possibility of correct calculations of both broadening and shift of HF lines by foreign gases were determined. Measurements for two foreign gases (Ar and N2 for which there are literature data) were made in order to test this approach. The obtained results have been well matched with existing literature data. After that, measurements were carried out on two transitions P(7) and P(8) for SF6 (for which neither broadening nor the shift are known) and for H2 (only broadening is known for overtone band). The obtained results were compared with scarce literature data.
Abstract A vibration-rotation band system of acetylene of the /Πu bending vibration v5 has been recorded with high resolution by a Bruker IFS 120 HR Michelson spectrometer. From the analysis of the hot band of the normal isotopic species, v4 + v5 - v4, and the fundamental band of HC13CH in natural abundance an improved set of constants has been derived. The intensity perturbation due to the l-type resonance has been clearly observed in the band system v4 + v5 -v4
The dynamical problem of the “diatomic molecule” is solved on the new mechanics. The terms of the rotational energy are , where ; the weights of the corresponding states are 2m; the frequencies differ a little from the classical ones. Finally the intensities are slightly different from those computed by Kemble; the main term agrees with that of Fowler, but the positive branch is only slightly stronger than the negative. The central line vanishes. The intensities are valid only for the fundamental band.
The equivalent widths of 16 lines in the fundamental vibration–rotation band of the H79Br molecule are measured in the linear region of the curve-of-growth method. The measurements are made on a Littrow type high-resolution infrared grating spectrometer in a double-pass manner so that the two isotopic lines of H79Br and H81Br, which are separated by approximately 0.4 cm−1, could be completely resolved. From the measurements of equivalent widths, the strengths and squares of the dipole matrix elements for the spectral lines are calculated. This is the first time the high-resolution work on the fundamental band has ever been presented. The present high-resolution values are found to be approximately one-half of the values of an earlier low-resolution work.
Widths and strengths of vibration-rotation lines in the fundamental band of nitric oxide