Theory of moments and modelling of non-Markovian relaxation matrix for colliding linear rotators

Результат исследований: Материалы конференцийтезисырецензирование


Although the effects caused by collisions with finite durations have inarguable importance for
theoretical gas-phase spectroscopy, their quantitative picture is still deficient. This circumstance sets
obstacles to the progress of terrestrial and venusian atmospheric studies urgently demanding higher
accuracy of spectroscopic data modelling. The commonly used impact (Markov) theory can accurately
predict [1] the collisional effects on separated lines as well as on the narrow isotropic Raman bands but fails
in the broader frequency ranges typical to the IR absorption and anisotropic Raman bands. Simulations of the
collisional line mixing effects in such bands should therefore exploit the frequency-dependent relaxation
matrices Γ( ) ω satisfying the fundamental sum rules [2], for the latter hold only in the non-Markov domain.
Assuming fast dynamics patterns for colliding pairs of linear rotators, we have recently expressed [3]
Γ( ) ω via the one-sided Fourier transforms of the time correlation functions of anisotropic-interaction terms.
The collision-induced shapes [4] suggest suitable functional forms of these transforms successfully tested for
the linear molecule – atom case [5]. Following a suggestion given in [3], in the present work we use theory
of moments to strictly fix parameters of such trial Fourier-transform functions. To that end, the formulas of
leading moments, M0 and M2, are derived classically, with the full allowance for the anisotropy of potential
and of distribution function. A computer code for these moments is advanced. The results for the test N2–N2
system respond well to the available sets of data and thus open up encouraging opportunities for studies of
other practically important systems, CO2–CO2 being the prime target.
The Russian co-authors thank RFBR for financial support (project 19-03-00830).
1. J.-M. Hartmann et al., J. Quant. Spectrosc. Radiat. Transfer 213, 178–227 (2018).
2. N.N. Filippov, M.V. Tonkov, J. Chem. Phys. 108, 3608–3619 (1998).
3. A.P. Kouzov, J.V. Buldyreva, A.V. Sokolov, J. Chem. Phys. 149, 044305 (2018).
4. L. Frommhold, Collision-Induced Absorption in Gases (Cambridge, Cambridge University Press, 1993).
5. A.P. Kouzov, Phys. Rev. A 60, 2931–2939 (1999)
Язык оригиналаанглийский
СостояниеОпубликовано - 1 июл 2019
СобытиеXIX Symposium on High Resolution Molecular Spectroscopy - Nizhny Novgorod, Российская Федерация
Продолжительность: 1 июл 20195 июл 2019
Номер конференции: 19


конференцияXIX Symposium on High Resolution Molecular Spectroscopy
Сокращенный заголовокHighRus-2019
СтранаРоссийская Федерация
ГородNizhny Novgorod
Адрес в сети Интернет