src/gromacs/applied-forces/electricfield.h

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  35 #ifndef GMX_APPLIED_FORCES_ELECTRICFIELD_H
  36 #define GMX_APPLIED_FORCES_ELECTRICFIELD_H
  37
  38 #include <memory>
  39
  40 namespace gmx
  41 {
  42
  43 class IMDModule;
  44
  45 /*! \brief
  46  * Creates a module for an external electric field.
  47  *
  48  * The returned class describes the time dependent electric field that can
  49  * be applied to all charges in a simulation. The field is described
  50  * by the following:
  51  *     E(t) = A cos(omega*(t-t0))*exp(-sqr(t-t0)/(2.0*sqr(sigma)));
  52  * If sigma = 0 there is no pulse and we have instead
  53  *     E(t) = A cos(omega*t)
  54  *
  55  * force is kJ mol^-1 nm^-1 = e * kJ mol^-1 nm^-1 / e
  56  *
  57  * WARNING:
  58  * There can be problems with the virial.
  59  * Since the field is not self-consistent this is unavoidable.
  60  * For neutral molecules the virial is correct within this approximation.
  61  * For neutral systems with many charged molecules the error is small.
  62  * But for systems with a net charge or a few charged molecules
  63  * the error can be significant when the field is high.
  64  * Solution: implement a self-consistent electric field into PME.
  65  */
  66 std::unique_ptr<IMDModule> createElectricFieldModule();
  67
  68 } // namespace gmx
  69
  70 #endif