For POTEntial=BIHArmonic, a two-sided harmonic
function is used:

(20.7)

(20.8)

where
is the scale factor specified by the SCALe statement, is the
Boltzmann constant, is the temperature specified by the
TEMPerature
statement,
is specified by the CEILing statement,
, , and are specified by the
ASSIgn
statement:

The distance is defined in Section 20.2.
The deviation is
defined as .