Butadiene CSF Optimization¶

This tutorial demonstrates the simultaneous optimization of Jastrow, Orbitals, and Configuration State Functions (CSFs) for Butadiene.

System Configuration¶

Molecule: Butadiene
Expansion: 20 Determinants + 12 CSFs
Basis: BFD-Q (Quadruple-zeta)

Input File Setup¶

Input File: vmc_optall_ci44.inp

%module general
    title        'butadiene ci44 vmc calculation with 20 dets and 12 csf'
    pseudopot    BFD
    basis        BFD-Q
    mode         'vmc_one_mpi'
%endmodule

load determinants    champ_v2_gamess_ci44_pVQZ_cart.det
load orbitals        champ_v3_trexio_order_champ_v2_gamess_ci44_pVQZ_cart.lcao
load symmetry        champ_v2_gamess_ci44_pVQZ_cart.sym
load jastrow         jastrow_good_b3lyp.0

%module optwf
    ioptwf        1
    ioptci        1       # Optimize CSF coefficients
    ioptjas       1       # Optimize Jastrow
    ioptorb       1       # Optimize Orbitals
    method        'sr_n'
    ncore         0
    nextorb       280
%endmodule

Note¶

CSFs are linear combinations of determinants that respect the spin and spatial symmetry of the state. Optimizing CSFs instead of individual determinants preserves these symmetries.

Resources: Butadiene CSF Test