Eur. Phys. J. D (2014) 68: 59
https://doi.org/10.1140/epjd/e2014-40749-7

Regular Article

Time-efficient numerical simulation of diatomic molecular spectra

Institute of Physics, Bijenička cesta 46, 10000 Zagreb, Croatia

^a e-mail: horvatic@ifs.hr

Received: 28 November 2013
Received in final form: 21 January 2014
Published online: 27 March 2014

Abstract

We present a quantum-mechanical procedure for calculating the photoabsorption spectra of diatomic molecules, entirely based on the Fourier grid Hamiltonian method for obtaining energies and the corresponding wave functions. Discrete and continuous spectrum contributions, which are the result of transitions between bound, free, and quasibound states of diatomic molecules were treated on the same footing. Using the classical Franck-Condon principle and the stationary-phase approximation, we also developed a “semiquantum” simulation method of the spectrum which allows an extremely time-efficient numerical algorithm, reducing the computer time by up to four orders of magnitude. The proposed method was tested on the absorption spectra of potassium molecules.