src/types/MorseBondType.hpp

#ifndef TYPES_MORSEBONDTYPE_HPP
#define TYPES_MORSEBONDTYPE_HPP

#include "types/BondType.hpp"

namespace oopse {
  /**
   * @class MorseBondType 
   *
   * MorseBondType is a more realistic bond potential.
   *
   * The functional form is given by: \f$V(r) = D_e (1 - e^{-\beta (r
   * - r_0)})^2\f$ where \f$D_e\f$ is the bond dissociation energy (in
   * kcal / mol), \f$\beta$\f is an inverse distance parameter related
   * to the force constant. \f$\beta = \sqrt{\frac{k}{2 D_e}}\f$, and
   * \f$r_0\f$ is the equilibrium bond length.
   */
  class MorseBondType : public BondType {
    
  public:

    MorseBondType( double myR0, double myD, double myBeta) 
        : BondType(myR0), De(myD), beta(myBeta) {
    }
    
    void setWellDepth(double myD) { De = myD;}

    void setBeta(double myBeta) { beta = myBeta; }

    void setWellDepthAndForceConstant(double myD, double myK) {
      De = myD;
      beta = sqrt(myK/(2.0*De));
    }

    double getWellDepth() {return De;}

    double getBeta() {return beta;}

    double getForceConstant() {return 2.0*De*beta*beta;}

    virtual void calcForce(double r, double& V, double& dVdr) {
      double dr, eterm, eterm2;

      dr = r - r0;
      eterm = exp(-beta*dr);
      eterm2 = eterm*eterm;

      V = De*(1 - 2.0*eterm  + eterm2);
      dVdr = 2.0 * De * beta * (eterm - eterm2);
    }
                
  private:
    
    double De;
    double beta;
    
  };
}
#endif
Revision:	1748
Committed:	Wed Nov 17 21:47:42 2004 UTC (19 years, 9 months ago) by tim
File size:	1434 byte(s)
Log Message:	UreyBradleyBend and GhostBend
#	User	Rev	Content
1	gezelter	1743	#ifndef TYPES_MORSEBONDTYPE_HPP
2			#define TYPES_MORSEBONDTYPE_HPP
3
4			#include "types/BondType.hpp"
5
6			namespace oopse {
7			/**
8			* @class MorseBondType
9			*
10			* MorseBondType is a more realistic bond potential.
11			*
12			* The functional form is given by: \f$V(r) = D_e (1 - e^{-\beta (r
13			* - r_0)})^2\f$ where \f$D_e\f$ is the bond dissociation energy (in
14			* kcal / mol), \f$\beta$\f is an inverse distance parameter related
15			* to the force constant. \f$\beta = \sqrt{\frac{k}{2 D_e}}\f$, and
16			* \f$r_0\f$ is the equilibrium bond length.
17			*/
18			class MorseBondType : public BondType {
19
20			public:
21
22	tim	1746	MorseBondType( double myR0, double myD, double myBeta)
23			: BondType(myR0), De(myD), beta(myBeta) {
24	gezelter	1743	}
25
26			void setWellDepth(double myD) { De = myD;}
27	tim	1746
28	gezelter	1743	void setBeta(double myBeta) { beta = myBeta; }
29	tim	1746
30	gezelter	1743	void setWellDepthAndForceConstant(double myD, double myK) {
31			De = myD;
32			beta = sqrt(myK/(2.0*De));
33			}
34
35			double getWellDepth() {return De;}
36	tim	1746
37	gezelter	1743	double getBeta() {return beta;}
38	tim	1746
39	gezelter	1743	double getForceConstant() {return 2.0Debeta*beta;}
40
41	tim	1748	virtual void calcForce(double r, double& V, double& dVdr) {
42	gezelter	1743	double dr, eterm, eterm2;
43
44			dr = r - r0;
45			eterm = exp(-beta*dr);
46			eterm2 = eterm*eterm;
47
48			V = De(1 - 2.0eterm + eterm2);
49			dVdr = 2.0 * De * beta * (eterm - eterm2);
50			}
51
52			private:
53
54			double De;
55			double beta;
56
57			};
58			}
59			#endif