On the ambiguity of the intermolecular interaction potential determined from spectroscopic data

It was shown that the interaction potential for NH₃-Ar and NH₃-He systems is determined ambiguously from experimentally measured broadening coefficients γ of NH₃ absorption lines. Different sets of model interaction potentials, given the same calculation accuracy of the coefficients of broadening by pressure of these gases at room temperature, determine these coefficients for other temperatures in different ways. This difference is the most pronounced for NH₃ lines in a NH₃-He mixture. For NH₃ lines in a NH₃-Ar mixture, this difference becomes apparent for lines with small rotational quantum numbers K; this effect weakens for K → J.