DIHEdral { restraints-dihedral-statement } END
is invoked from the main level of X-PLOR. Invocation
automatically turns on the CDIH energy flag (Section 4.5).
restraints-dihedral-statement:==
ASSIgn
selection selection
selection selection real real
real integer adds a new dihedral
angle to the restraints-dihedral database.
The four selections have to be unique;
i.e., each selection must select exactly one
atom. The selections
determine the four atoms that specify the dihedral
angle. The first real number specifies
the energy constant () in kcal mole rad, the
second real number specifies the angle in degrees to which the
dihedral angle is restrained (), the third real
number specifies the range around the
restrained angle (), and the integer number
specifies the exponent ().
NASSign=integer
is a required parameter that specifies
the maximum expected number of assignments.
It has to be greater than or
equal to the actual number
(default: 400).