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the_nevpt2_program [2020/06/11 18:17]
127.0.0.1 external edit |
the_nevpt2_program [2021/05/27 16:33] (current)
werner [General considerations] |
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| NEVPT2 has been implemented in two variants both of which are present in ''MOLPRO'', these are the //strongly contracted// (SC) and the //partially contracted// (PC) variants. The two variants differ by the number of perturber functions employed in the perturbation summation. The PC–NEVPT2 uses a richer function space and is in general more accurate than the SC–NEVPT2. The results of SC–NEVPT2 and PC–NEVPT2 are anyway usually very close to one another. | NEVPT2 has been implemented in two variants both of which are present in ''MOLPRO'', these are the //strongly contracted// (SC) and the //partially contracted// (PC) variants. The two variants differ by the number of perturber functions employed in the perturbation summation. The PC–NEVPT2 uses a richer function space and is in general more accurate than the SC–NEVPT2. The results of SC–NEVPT2 and PC–NEVPT2 are anyway usually very close to one another. |
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| | Since Molpro2021.2, density fitting can be used to compute the integrals, and the program is then called with |
| | ''DF-NEVPT2''. |
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| ===== Input description ===== | ===== Input description ===== |