'''Different water models and related constants'''
import quantities as pq
[docs]class TIP4P():
'''The TIP4P water model.
Attributes
----------
epsilon_S
The relative dielectric constant of TIP4P water.
gamma_s
quadrupole-moment trace of the solvent model.
'''
# For tip4p=51: https://pubs.rsc.org/en/content/articlelanding/2011/CP/c1cp22168j#!divAbstract
epsilon_S = 51
# For TIP4P = * hydrogen charge * OH bond length ^2 + MW charge * OD bond length ^2
gamma_s = 2 * 0.52 * pq.e * (0.09572 * pq.nm) ** 2 + -1.04 * pq.e * (
0.015 * pq.nm) ** 2
[docs]class TIP3P():
'''The TIP3P water model.
Attributes
----------
epsilon_S
The relative dielectric constant of TIP4P water.
gamma_s
quadrupole-moment trace of the solvent model.
'''
# epsilon_S is the static relative dielectric permittivity of the solvent, for TIP3 is 97.
epsilon_S = 97
# For TIP3P, it is 0.00764 e nm2 = 2 * hydrogen charge [0.417*pq.e] * OH bond length (0.09572*pq.nm)**2
gamma_s = 2 * 0.417 * pq.e * (0.09572 * pq.nm) ** 2