Geometry Optimization

It is possible to perform geometry optimization calculation of the target molecule using Berny algorithm before the VQE and chemical property calculations. The algorithm chosen at solver is used for energy evaluation while geometry optimization is performed.

Options

  • target_state: Specifies the state index of which the eigenenergy is minimized during geometry optimization

  • excited_state_type: If target_state is set to equal or larger than 1, the method for calculating electronically excited states can be selected from the following:

    • STATE_AVERAGED : the default, where each electronic excited state is equally weighted.

    • STATE_SPECIFIC

  • weights: The weight of state-average can be specified as a list. If not given, equal weighting is applied.

The following fields specify convergence criteria:

  • gradientmax: the maximum force component (in a.u.)

  • gradientrms: the root-mean square force (in a.u.)

  • stepmax: the maximum step component (in Bohr)

  • steprms: the root-mean-square step (in Bohr)

  • maxsteps: the maximum number of steps

Notes

Geometry optimization is not supported when:

  • the system with spatially periodic boundary condition (Target Periodic System) is subject to calculation

  • density fitting approximation is used

  • MCVQE is chosen for Solver

Input example

"geometry_optimization": {
  "target_state": 0,
  "gradientmax": 1e-4,
  "gradientrms": 1e-4,
  "stepmax": 2e-2,
  "steprms": 1.5e-2,
  "maxsteps": 1000,
}