Dynamics_Langevin_Verlet contains a procedure for performing Langevin molecular dynamics simulations.
This module is a new one that is not described in the book A Practical Introduction to the Simulation of Molecular Systems.
Module | Variables |
---|---|
CONSTANTS | AMU_TO_KG, KBOLTZ, MS_TO_APS |
DEFINITIONS | DP |
IO_UNITS | OUTPUT |
RANDOM_NUMBERS | RANDOM_GAUSS |
STATUS | ERROR |
ATOMS | ATMCRD, ATMFIX, ATMMAS, NATOMS, NFREE |
DYNAMICS_UTILITIES | Most of the public items in the module. |
VELOCITY | ATMVEL, EKE, TEMPERATURE, VELOCITY_TEMPERATURE |
None.
There is a single public subroutine in this module.
Subroutine | Purpose |
---|---|
LANGEVIN_VERLET_DYNAMICS | Perform a molecular dynamics simulation using a Langevin velocity Verlet algorithm. |
Argument | Type | Intent | Optional | Purpose |
---|---|---|---|---|
TBATH | Real | In | No | The Langevin bath temperature in Kelvin. |
GAMMA | Real | In | No | The collision frequency in ps-1. |
Error | Meaning |
---|---|
Invalid TBATH for Langevin dynamics. | TBATH has a value of zero or less. |
Invalid GAMMA for Langevin dynamics. | GAMMA has a value of zero or less. |
No velocities exist. | No velocities have been assigned. |
The option of having different collision frequencies for different atoms may be added. Otherwise, stable.