ИСТИНА

The classical impact theory of Gordon [1] is applied to calculate half-widths and shifts of 12C16O rotational spectral lines broadened by Ar. Classical trajectory 3D calculations of CO-Ar binary collisions are performed on the most accurate ab initio potential energy surface [2] developed into Legendre polynomial series up to lmax=15. Broadening and shifting coefficients of 12C16O lines with J values from 0 to 21 are examined in a broad temperature interval (T = 100–400 K). The results of classical calculations are in good agreement with different available measurements.The Birnbaum [3] profile is applied to model CO non-impact (i.e., non-Lorentzian) lineshapes taking into account finite duration of collisions. Direct classical trajectory approach (instead of that proposed by Birnbaum) is used to estimate an average collision time for selected J and T values. The authors received financial support from the Ministry of Science and Higher Education within the State assignment FSRC «Crystallography and Photonics» RAS and RFBR-CNRS (Project No.18-55-16006). References: 1. R.G. Gordon, J. Chem. Phys. 44, 3083-3089 (1966); ibid., 45, 1649-1655 (1966). 2 R.R. Toczylowski, S.M. Cybulski, J. Chem. Phys. 112, 4604–4612 (2000); T.B. Pedersen, J.L. Cacheiro, B. Fernandez, H. Koch, ibid., 117, 6562–6572 (2002). 3. G. Birnbaum, J. Quant. Spectrosc. Radiat. Transfer. 21, 597-607 (1979).