Linear transitions to highly excited stretching vibrations of molecular groups

The Wentzel–Kramers–Brillouin approximation is used to calculate the intensity of transitions to highly excited stretching vibrations of molecular groups. The problem was solved using the three-dimensional single-particle potential approximation. The limits of validity of the local mode model are identified. Calculations are made of the wavelengths and intensities of transitions accompanied by excitation of overtones of stretching vibrations of hydrogen in the benzene ring. The results of the calculations are compared with an experiment to measure the transmission of a polystyrene fiber-optic line.