Influence of the intramolecular potential of adsorbed hydrogen on frequency shift calculations

The influence of the choice of the intramolecular potential on the resulting frequency shift of the fundamental vibrational transition in the dihydrogen molecule adsorbed on zeolite NaA is estimated. It is shown that an improved Morse potential and the potential calculated by Kołtsos and Wolniewicz lead to the same frequency shift value. Application of the Buckingham method for the frequency shift calculation to this case is discussed.