The descriptor file must contain the following line at the start of the file.
DES1 code Natom
The word DES1 must appear starting on column one, line one of the file and the numbers code and Natom must follow this word on line one. DES1 identifies this as a descriptor file. code is a number used by analysis programs. Numbers 0-999 are reserved. Natom is the number of atoms in the system defined by this descriptor. Except for the file and record identifiers (these must start on column 1), the descriptor can be in any reasonable format. Note that the number of atoms, the number of atom types and the number of groups are listed in several places in the descriptor file. In general, these numbers must agree.
Example:
DES1 1 3212
An example descriptor header line for a system of 3212 atoms.
The descriptor uses an internal system of units as follows:
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The Computational Energy Unit or CEU is equal to amu Å2 ps-2. Some useful equivalents:
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