Abstract.
We present a detailed investigation of the perturbation approach for calculating zero-point vibrational contributions to molecular properties. It is demonstrated that if the sum of the potential energy and the zero-point vibrational energy is regarded as an effective potential energy, the leading contribution to the first-order wave function vanishes in the perturbation approach. Two different perturbation approaches have been investigated numerically by calculations of some magnetic properties for a few diatomic molecules and the results obtained have been compared to the exact numerical results. It is shown that only a few terms need to be included in a perturbation expansion to obtain an accuracy in the calculated rovibrational contribution better than the quality normally obtained for the potential and property surfaces in electronic structure calculations.
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Received: 16 April 1999 / Accepted: 1 July 1999 / Published online: 4 October 1999
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Åstrand, PO., Ruud, K. & Sundholm, D. A modified variation–perturbation approach to zero-point vibrational motion. Theor Chem Acc 103, 365–373 (2000). https://doi.org/10.1007/s002149900078
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DOI: https://doi.org/10.1007/s002149900078