Example: intermediate data preparation for the ground electronic state of AlH

The implementation of direct summation technique requires the construction of the whole set of vibrational-rotational levels for all electronic states. Experimental data as a rule refer to low-lying vibrational and rotational levels. Dissociation energy value and the construction of the Limiting Curve of Dissociation (LCD) allows the extrapolation of the experimental data with the description of all bound and quasibound states.

The results of calculations of rotational levels for the selected vibrational quantum number are presented in the figure. It should be noted that only four vibrational levels of the ground state of the AlH molecule are investigated in the spectroscopic studies.