Light.hpp

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 * [1] Meineke, et al., J. Comp. Chem. 26, 252-271 (2005).
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 * [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).
 */
 
/*! \file perturbations/Light.hpp
    \brief Rotating Electric Field perturbation
*/
 
#ifndef PERTURBATIONS_LIGHT_HPP
#define PERTURBATIONS_LIGHT_HPP
 
#include <complex>
 
#include "brains/ForceModifier.hpp"
#include "brains/SimInfo.hpp"
#include "perturbations/LightParameters.hpp"
 
namespace OpenMD::Perturbations {
 
  //! Applies an EM field representing light to the system
  /*! The field is applied as an external perturbation.  The user specifies
 
  \code{.unparsed}
    light{
      useLight = true;
      intensity = c;
      wavelength = l;
      propagationDirection = (0, 0, 1);
      polarization = "+";
    }
  \endcode
 
    in the .omd file where the propagationDirection vector, \f$
    \mathbf{k} \f$ is a unit vector, the value of \f$ c \f$ is in
    units of \f$ W cm^{-2} \f$, and wavelength, \f$ l \f$ is in nm.
 
    Alternatively, the user can specify
 
  \code{.unparsed}
    light{
      useLight = true;
      intensity = c;
      frequency = w;
      propagationDirection = (0, 0, 1);
      polarization = "+";
    }
  \endcode
 
   with frequency, \f$ w \f$ measured in Hz, or alternatively:
 
  \code{.unparsed}
    light{
      useLight = true;
      intensity = c;
      waveVector = (kx, ky, kz);
      polarization = "+";
    }
  \endcode
 
  with the components of the wavevector specified in \f$ \AA^{-1} \f$.
  In all cases, options for polarization include "x", "y", "+", or "-".
 
  */
  class Light : public ForceModifier {
  public:
    Light(SimInfo* info);
 
  private:
    void modifyForces() override;
    void initialize();
 
    bool initialized;
    bool doLight;
    bool doParticlePot;
 
    SimInfo* info_;
    Perturbations::LightParameters* lightParams;
    Vector3d khat_;
    Vector3d k_;
    RealType omega_;
    RealType lambda_;
    RealType kmag_;
    RealType E0_;
    std::vector<std::complex<RealType>>
        jones_;  // Jones vector for polarization
    RotMat3x3d A_;
    RotMat3x3d Ainv_;
 
    enum LightPolarization {
      lightX,      // x-plane polarized light
      lightY,      // y-plane polarized light
      lightPlus,   // circularly polarized light (clockwise)
      lightMinus,  // circularly polarized light (counterclockwise)
      lightUnknownPolarization
    };
  };
}  // namespace OpenMD::Perturbations
 
#endif