Every Force Parameter file must have a header line consisting of two words: :CONSTANTS Version-string-with-no-spaces Starting on column one of line one must be a keyword which is exactly ":CONSTANTS". This is followed by a second word which must have no white space and is 63 characters or shorter. This is called the version string and it is a word that is used to identify the force field. Force field assembly programs will register version strings that they are compatible with. An assembly program has to make use of only the names declared in a force field. If there is even a slight variation, such as the header keyword appearing on column two or line two, the file will be deemed not to be a force constants file. 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