BuckinghamInteractionType.hpp

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 * work.  Good starting points are:
 *
 * [1] Meineke, et al., J. Comp. Chem. 26, 252-271 (2005).
 * [2] Fennell & Gezelter, J. Chem. Phys. 124, 234104 (2006).
 * [3] Sun, Lin & Gezelter, J. Chem. Phys. 128, 234107 (2008).
 * [4] Vardeman, Stocker & Gezelter, J. Chem. Theory Comput. 7, 834 (2011).
 * [5] Kuang & Gezelter, Mol. Phys., 110, 691-701 (2012).
 * [6] Lamichhane, Gezelter & Newman, J. Chem. Phys. 141, 134109 (2014).
 * [7] Lamichhane, Newman & Gezelter, J. Chem. Phys. 141, 134110 (2014).
 * [8] Bhattarai, Newman & Gezelter, Phys. Rev. B 99, 094106 (2019).
 */
 
#ifndef TYPES_BUCKINGHAMINTERACTIONTYPE_HPP
#define TYPES_BUCKINGHAMINTERACTIONTYPE_HPP
 
#include "types/NonBondedInteractionType.hpp"
 
namespace OpenMD {
  /**
   * @class BuckinghamInteractionType
   *
   * BuckinghamInteractionType is one of the basic non-bonded
   * interactions for representing the non-Coulombic contribution in
   * ionic and networked solids like silica and alumina. The
   * Traditional form has an exponential-6 form, which diverges to
   * negative infinity at short distances. The modified form corrects
   * the divergence with a short range 30-6 potential.
   *
   * Traditional:
   *
   * \f[ V = A \exp( -B r) - \frac{C}{r^6} \f]
   *
   * Modified:
   *
   * \f[ V = A \exp( -B r) - \frac{C}{r^6} + 4 \epsilon \left( \left(
   * \frac{\sigma}{r} \right)^{30} - \left( \frac{\sigma}{r} \right)^6 \right)
   * \f]
   */
 
  enum BuckinghamType { btTraditional, btModified, btUnknown };
 
  class BuckinghamInteractionType : public NonBondedInteractionType {
  public:
    BuckinghamInteractionType(RealType myA, RealType myB, RealType myC,
                              BuckinghamType myType) {
      A               = myA;
      B               = myB;
      C               = myC;
      interactionType = myType;
      setBuckingham();
    }
 
    BuckinghamInteractionType(RealType myA, RealType myB, RealType myC,
                              RealType mySigma, RealType myEpsilon,
                              BuckinghamType myType) {
      A               = myA;
      B               = myB;
      C               = myC;
      sigma           = mySigma;
      epsilon         = myEpsilon;
      interactionType = myType;
      setBuckingham();
    }
 
    RealType getA() { return A; }
 
    RealType getB() { return B; }
 
    RealType getC() { return C; }
 
    RealType getSigma() { return sigma; }
 
    RealType getEpsilon() { return epsilon; }
 
    BuckinghamType getInteractionType() { return interactionType; }
 
  private:
    RealType A;
    RealType B;
    RealType C;
    RealType sigma;
    RealType epsilon;
    BuckinghamType interactionType;
  };
}  // namespace OpenMD
 
#endif