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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.
 +
 +Since Molpro2021.2, density fitting can be used to compute the integrals, and the program is then called with
 +''DF-NEVPT2''.
  
 ===== Input description ===== ===== Input description =====