THEORETICAL INVESTIGATION INTO DIPOLE-MOMENT FUNCTIONS OF HF, HCl, AND HBr MOLECULES AT SMALL INTERNUCLEAR SEPARATIONS

Ab initio calculations of the dipole moment functions are performed within the united atom approximation in the first-order perturbation theory for the ground electronic states of HF, HCl and HBr molecules in the range of small internuclear separations. The calculation results are used for correction of the semi-empirical dipole-moment functions of these molecules obtained earlier.