Reduction of spectra to parameters of an effective diatomic Hamiltonian containing the generalized potential-energy function with correct long-range part. Application to ArH+ in the ground electronic state

Infrared and microwave spectra of ArH+ spanning more than half the potential well depth (in total 331 lines belonging to six isotopomers) are reduced to parameters of an effective Hamiltonian containing the generalized potential-energy function (GPEF) and adiabatic and nonadiabatic corrections. The reduced standard deviation of the fit is 0.831. The procedure ensures a qualitatively correct long-range behaviour of the diatomic potential: the GPEF of ArH+ reproduces the experimental value of the dissociation energy, has a correct R−4 asymptotic behaviour, and reproduces the limiting inverse-power long-range potential coefficient C4. The advantages of this method of solving the inverse spectral problem are demonstrated by comparison with previous analyses of spectral data of ArH+.