Based on a recent application of the collective model of coherent quadrupole–octupole oscillations and rotations in odd-mass nuclei we develop an algorithm for a microscopic calculation of the Coriolis interaction strength. It is realized by using the reflection asymmetric deformed shell model. The single-particle (s.p.) wavefunction is obtained in the basis of the axially deformed harmonic oscillator (ADHO). The Coriolis interaction strength is calculated after transforming the ADHO decomposition coefficients of the wavefunction into coefficients in the basis of the spherical harmonic oscillator (SHO). The transformation brackets relating the ADHO and SHO basis functions are numerically integrated. Calculations were implemented for several nuclei in which the parity doublet spectra are known or supposed to be built on a single-particle orbital with Ω = 1/2. The results show the applicability of this approach to study the effects of Coriolis interaction in nuclei with quadrupole and octupole deformations as well as to examine their s.p. and shape characteristics.