hessian¶
- psi4.driver.hessian(name, **kwargs)[source]¶
Function complementary to
frequency()
. Computes force constants, deciding analytic, finite difference of gradients, or finite difference of energies.- Returns:
Matrix
– Total non-mass-weighted electronic Hessian in Hartrees/Bohr/Bohr.- Returns:
(
Matrix
,Wavefunction
) – Hessian and wavefunction when return_wfn specified.- Examples:
>>> # [1] Frequency calculation without thermochemical analysis >>> hessian('mp3')
>>> # [2] Frequency calc w/o thermo analysis getting the Hessian >>> # in file, core.Matrix, and np.array forms >>> set hessian_write on >>> H, wfn = hessian('ccsd', return_wfn=True) >>> wfn.hessian().print_out() >>> np.array(H)