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PSB Multi-State Optimization

This tutorial demonstrates Multi-State Optimization using the mix_n method for PSB (Penta-2,4-dieniminium) molecules.

System Configuration

  • Molecule: PSB2 / PSB3
  • Method: mix_n (mixtures of normal distributions? or mixed state optimization)
  • Target: Optimizing multiple states simultaneously (Ground + Excited).

Input File Setup

Input File: revised_psb2_mix_n.inp

%module general
    title           'psb-20'
    weights         [ 1.0d0,  1.0d0 ]  # Weights for state averaging
    weights_guiding [ 1.0d0,  1.0d0 ]
    mode            'vmc_one_mpi'
%endmodule

%module mstates
    iguiding        2      # Number of guiding states / states to optimize
    iefficiency     1
%endmodule

load molecules       ...
load determinants    champ_v2_gamess_PSB2_casci44.det
# ...

%module optwf
    ioptwf        1
    ioptci        1
    ioptjas       1
    ioptorb       1
    method        'mix_n'  # Multi-state optimization method
    ncore         0
    nextorb       86
%endmodule

Significance

Multi-state optimization is critical for correctly describing regions of potential energy surfaces where states utilize, such as conical intersections. The weights keyword controls the balance between states in the penalty function.

Resources: PSB2 Test