qrunch.chemistry.calculators.mp2_calculator

Ground state energy calculator using second-order Møller-Plesset (MP2) perturbation theory.

Note that the ground_state_problem may restrict the orbital space, in which case this is not a standard MP2 calculation but a calculation with a truncated orbital space. In case of a restricted orbital space the inactive energy contribution associated with the active space is included in the ground_state_problem.

Classes

MollerPlesset2GroundStateCalculator

Class for performing second-order Møller-Plesset (MP2) calculations.

class MollerPlesset2GroundStateCalculator

Bases: object

Class for performing second-order Møller-Plesset (MP2) calculations.

__init__(options: MollerPlesset2GroundStateProblemCalculatorOptions | None = None) → None

Initialize an instance of MollerPlesset2GroundStateCalculator.

Parameters:: options (MollerPlesset2GroundStateProblemCalculatorOptions | None) – Options to use for the calculation. None results in default options.
Return type:: None

calculate(problem: GroundStateProblem) → GroundStateProblemCalculatorResult

calculate(problem: ReactionPathProblem) → ReactionPathProblemCalculatorResult

Solve the second-order Møller-Plesset (MP2) problem.

Note that the ground_state_problem may restrict the orbital space, in which case this is not a standard MP2 calculation but a calculation with a truncated orbital space. In case of a restricted orbital space the inactive energy contribution associated with the active space is included in the ground_state_problem.

The Hamiltonian for all geometries is assumed to be real.

Parameters:: problem (RestrictedGroundStateProblem | UnrestrictedGroundStateProblem | RestrictedReactionPathProblem | UnrestrictedReactionPathProblem) – The problem to calculate the ground state energy / energies for.
Return type:: GroundStateProblemCalculatorResult | ReactionPathProblemCalculatorResult