Sto3g.h

/* Copyright 2019 Kristofer Björnson
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


#ifndef COM_DAFER45_TBTK_STO3G
#define COM_DAFER45_TBTK_STO3G

#include "TBTK/AbstractState.h"
#include "TBTK/Atom.h"
#include "TBTK/KineticOperator.h"
#include "TBTK/NuclearPotentialOperator.h"
#include "TBTK/HartreeFockPotentialOperator.h"

namespace TBTK{

class Sto3g : public AbstractState{
public:
    Sto3g(
        double slaterExponent,
        const std::vector<double> &coordinates,
        const Index &index,
        int spinIndex = -1
    );

    virtual Sto3g* clone() const;

    virtual std::complex<double> getOverlap(
        const AbstractState &ket
    ) const;

    virtual std::complex<double> getMatrixElement(
        const AbstractState &ket,
        const AbstractOperator &o
    ) const;
private:
    double contractionCoefficients[3] = {0.444635, 0.535328, 0.154329};

    double gaussianExponents[3];

    int spinIndex;

    std::complex<double> getKineticTerm(
        const Sto3g &ket,
        const KineticOperator &o
    ) const;

    std::complex<double> getNuclearPotentialTerm(
        const Sto3g &ket,
        const NuclearPotentialOperator &o
    ) const;

    std::complex<double> getHartreeFockPotentialTerm(
        const Sto3g &ket,
        const HartreeFockPotentialOperator &o
    ) const;

    std::complex<double> getSingleHartreeFockTerm(
        const Sto3g &state1,
        const Sto3g &state2,
        const Sto3g &state3
    ) const;

    static double F_0(double x);
};

inline Sto3g* Sto3g::clone() const{
    return new Sto3g(*this);
}

};  //End of namespace TBTK

#endif