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molecular_geometry [2023/06/01 13:43] – [Counterpoise calculations] peterkmolecular_geometry [2024/01/08 13:24] (current) – external edit 127.0.0.1
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 ''COUNTERPOISE'' [, //key1=value, key2=value,…...//] ''COUNTERPOISE'' [, //key1=value, key2=value,…...//]
  
-Without any options, this will calculate the ghost-orbital corrections to dimer interaction energies using the last energy calculation to define the dimer and the methods to be used. First of all, the molecule is automatically partitioned into fragments. This is done by assigning all interatomic distances as either intra- or intermolecular, comparing the distance with the scaled sum of Bragg radii of the two atoms. The default scale factor is 1.4, but it can be changed with ''SCALE=''//scale//; for the S66 database of intermolecular interactions, correct partitioning is obtained with a scale factor in the range 1.2 to 1.9. If all of the distances are intramolecular, then it will be assumed that the system is not a non-bonded complex, and the counterpoise calculation will not be done at all. This gives support for running the same Molpro input for both dimers and monomers. At present, partitioning into more than two fragments is discovered, but there is no supporting implementation of the counterpoise correction.+Without any options, this will calculate the ghost-orbital corrections to dimer interaction energies using the last energy calculation to define the dimer and the methods to be used. First of all, the molecule is automatically partitioned into fragments. This is done by assigning all interatomic distances as either intra- or intermolecular, comparing the distance with the scaled sum of Bragg radii of the two atoms. The default scale factor is 1.4, but it can be changed with ''SCALE=''//scale//; for the S66 database of intermolecular interactions, correct partitioning is obtained with a scale factor in the range 1.2 to 1.95. If all of the distances are intramolecular, then it will be assumed that the system is not a non-bonded complex, and the counterpoise calculation will not be done at all. This gives support for running the same Molpro input for both dimers and monomers. At present, partitioning into more than two fragments is discovered, but there is no supporting implementation of the counterpoise correction.
  
 The counterpoise procedure performs four calculations. For each of the identified monomers, it calculates the energy at the dimer geometry using first the dimer basis set, and secondly just the basis functions tied to the monomer atoms. The difference between these, the counterpoise correction, is reported, and added to the previously-calculated dimer energy. The counterpoise procedure performs four calculations. For each of the identified monomers, it calculates the energy at the dimer geometry using first the dimer basis set, and secondly just the basis functions tied to the monomer atoms. The difference between these, the counterpoise correction, is reported, and added to the previously-calculated dimer energy.