Study of anharmonic effects in the IR spectrum of a solution of CF3Br in liquid argon

摘要

The vibrational spectrum of CF3Br with the natural abundance ratio of isotopologues is studied in solutions in liquid Ar at T = 90 K in the frequency range 4000 - 400 cm(-1) with a resolution of 0.1 cm(-1) for the concentration range 3.1 x 10(-7) - 6.3 x 10(-3) mol %. The parameters of the vibrational spectrum of the molecule are determined: the frequencies are measured accurate to +/- 0.1 cm(-1), and the transition probabilities are found up to the fourth order inclusive. One hundred fifty absorption bands of CF3Br are interpreted, including the bands belonging to all the isotope modifications of this compound; the halfwidths of these bands are determined. For all the fundamental frequencies, the isotope shifts are obtained. Vibrational l- resonance is studied. Using the experimental data obtained and taking into account this resonance, a complete set of parameters describing the experimental frequencies with the error delta approximate to 0.3 cm(-1) was found. This set consists of 6 harmonic frequencies and 30 anharmonicity constants, including the constants r(ik) related to vibrational l-resonances.