TY - JOUR

T1 - Collision-induced double transition effects in the 3 nu(3) CO2 band wing region

AU - Filippov, NN

AU - Bouanich, JP

AU - Boulet, C

AU - Tonkov, MV

AU - LeDoucen, R

AU - Thibault, F

PY - 1997/2/8

Y1 - 1997/2/8

N2 - IR absorption beyond the head of the 00(0)3-00(0)0 (3 nu(3)) band of CO2 near 7000 cm(-1) has been analyzed. This absorption is found to consist of two comparable intensity contributions, namely, the allowed band wing and a collision-induced absorption (CIA) band. The band wing profile has been described by using a non-Markovian theory and the rotational perturbation densities for CO2-CO2 collisions, which was previously calculated from the intensity distribution in the high-frequency wing of the 00(0)1-00(0)0 CO2 band. The CIA component has a typical shape of CO2 CIA bands with the maximum at the double transition (00(0)1+00(0)2)-(00(0)0+00(0)0) frequency. The integrated binary coefficient of this CIA band was estimated to be B-2=(1.0+/-0.6)x10(-5) cm(-2) Amagat(-2). The CIA spectral moment theory has been used for the intensity calculation, which takes into account for the first time the collision-induced vibrational force field in CO2 pairs. By comparing the calculated and measured intensity for the double transition, the polarizability anisotropy matrix element for the 2 nu(3) band has been estimated as beta(20)=0.26+/-0.08 a.u., value in reasonable agreement with an independent estimation from previous results of polarizability matrix elements of CO2. (C) 1997 American Institute of Physics.

AB - IR absorption beyond the head of the 00(0)3-00(0)0 (3 nu(3)) band of CO2 near 7000 cm(-1) has been analyzed. This absorption is found to consist of two comparable intensity contributions, namely, the allowed band wing and a collision-induced absorption (CIA) band. The band wing profile has been described by using a non-Markovian theory and the rotational perturbation densities for CO2-CO2 collisions, which was previously calculated from the intensity distribution in the high-frequency wing of the 00(0)1-00(0)0 CO2 band. The CIA component has a typical shape of CO2 CIA bands with the maximum at the double transition (00(0)1+00(0)2)-(00(0)0+00(0)0) frequency. The integrated binary coefficient of this CIA band was estimated to be B-2=(1.0+/-0.6)x10(-5) cm(-2) Amagat(-2). The CIA spectral moment theory has been used for the intensity calculation, which takes into account for the first time the collision-induced vibrational force field in CO2 pairs. By comparing the calculated and measured intensity for the double transition, the polarizability anisotropy matrix element for the 2 nu(3) band has been estimated as beta(20)=0.26+/-0.08 a.u., value in reasonable agreement with an independent estimation from previous results of polarizability matrix elements of CO2. (C) 1997 American Institute of Physics.

KW - MOMENTS

KW - SHAPE

U2 - 10.1063/1.473140

DO - 10.1063/1.473140

M3 - статья

VL - 106

SP - 2067

EP - 2072

JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

SN - 0021-9606

IS - 6

ER -