The energy of the van der Waals contact between atoms i and j, Evdw-ij is: Evdw-ij =  Avdw-ij  -  Bvdw-ij rij12 rij6 where. rij is the distance between atoms i and j, Avdw-ij and Bvdw-ij are force parameters. This force term is available in two variants: Inclusion and Exclusion (described here). The van der Waals Exclusion record must appear only after the Atom Exclusion Types have been defined. The van der Waals Exclusion record has the following format: :VAN-DER-WAALS-EXCLUSION Avdw-1,1 Avdw-1,2 Avdw-1,3 ... ... Avdw-N-1,N-1 Avdw-N-1,N Avdw-N,N Bvdw-1,1 Bvdw-1,2 Bvdw-1,3 ... ... Bvdw-N-1,N-1 Bvdw-N-1,N Bvdw-N,N .END The opening keyword, like all keywords, begins with a colon and starts on column one of the line. If there are N Atom Exclusion Types, then N(N+1)/2 reciprocal 12 factors in units of Å12kcal/mol must follow the opening keyword and this must be followed by N(N+1)/2 reciprocal 6 factors in units of Å6kcal/mol. There is no terminating keyword but it is not a bad idea to close the record with a word that looks like the termination keyword, for example ".END". The numbers must be written in proper order, with the second index varying fastest. Any number of numbers may be placed on each line subject to the maximum width of a line of 1023 characters. There is no way to insert comments among the numbers. The mixing rules used to calculate the constants for mixed-pairs from values for pure-pairs should be documented in the source file. The program Yup.fpf will convert the force constants to internal units used by YUP and write these and the contact distances to the unformatted file: "van der Waals Exclusion Constants". Overview Exclusion Types Inclusion Types Exclusion Soft Spheres Exclusion van der Waals Bonds Angles Improper Torsions Distance NOE Torsion Power Series Exclusion Generalized LJ Header Check Inclusion Groups Inclusion Soft Spheres Inclusion van der Waals Hooke Hand Torsions Exclusion SwissCheese Angle NOE Inclusion Generalized LJ