- psi4.driver.hessian(name, **kwargs)¶
Function complementary to
frequency(). Computes force constants, deciding analytic, finite difference of gradients, or finite difference of energies.
Matrix– Total non-mass-weighted electronic Hessian in Hartrees/Bohr/Bohr.
>>> #  Frequency calculation without thermochemical analysis >>> hessian('mp3')
>>> #  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)