# Time-dependent Hartree-Fock response calculation¶

The computation of Hartree-Fock polarizabilities are currently available for restricted HF. A description of how to perform generic HF calculations are given in the Hartree-Fock calculation tutorial. In addition to the sections that are needed for a ground state HF calculation, the tdhf response keyword must be specified in the do section:

do
tdhf excited state
end do

Furthermore, you must add the solver tdhf response section and specify the frequencies for which you want to compute the polarizabilities, for instance:

solver tdhf es
frequencies: {0.0d0, 0.072d0, -0.072d0}
end solver tdhf es

A minimal working example is:

system
name: methanol
charge: 0
end system

do
tdhf response
end do

memory
available: 8
end memory

method
hf
end method

solver tdhf response
frequencies: {0.0d0, 0.072d0, -0.072d0}
end solver tdhf response

geometry
basis: cc-pVDZ
H        0.8475370000      0.0347360000      1.0345270000
C        0.3504820000      0.0067450000      0.0608350000
H        0.6350750000      0.8927640000     -0.5200650000
H        0.6629360000     -0.8933800000     -0.4828330000
O       -1.0108350000     -0.0082340000      0.3643870000
H       -1.4851950000     -0.0326310000     -0.4568520000
end geometry

If successful, you should find the polarizabilities for the desired frequencies at the end of the output file:

Determining TDHF polarizabilities
=================================

RHF polarizability for frequency  0.0000E+00:
--------------------------------------------
<< mu_x, mu_x >>:    -16.530473073826
<< mu_x, mu_y >>:     -0.053395729262
<< mu_x, mu_z >>:     -0.696915279065
<< mu_y, mu_x >>:     -0.053395729293
<< mu_y, mu_y >>:    -14.041555340045
<< mu_y, mu_z >>:     -0.042501961050
<< mu_z, mu_x >>:     -0.696915279078
<< mu_z, mu_y >>:     -0.042501961052
<< mu_z, mu_z >>:    -15.580356442772
--------------------------------------------

RHF polarizability for frequency  0.7200E-01:
--------------------------------------------
<< mu_x, mu_x >>:    -16.738269759140
<< mu_x, mu_y >>:     -0.053425576976
<< mu_x, mu_z >>:     -0.709938445749
<< mu_y, mu_x >>:     -0.053425576986
<< mu_y, mu_y >>:    -14.264814625850
<< mu_y, mu_z >>:     -0.042708032494
<< mu_z, mu_x >>:     -0.709938445776
<< mu_z, mu_y >>:     -0.042708032482
<< mu_z, mu_z >>:    -15.804021596120
--------------------------------------------

RHF polarizability for frequency -0.7200E-01:
--------------------------------------------
<< mu_x, mu_x >>:    -16.738269759140
<< mu_x, mu_y >>:     -0.053425576976
<< mu_x, mu_z >>:     -0.709938445749
<< mu_y, mu_x >>:     -0.053425576986
<< mu_y, mu_y >>:    -14.264814625850
<< mu_y, mu_z >>:     -0.042708032494
<< mu_z, mu_x >>:     -0.709938445776
<< mu_z, mu_y >>:     -0.042708032482
<< mu_z, mu_z >>:    -15.804021596120
--------------------------------------------

## Relevant input sections¶

solver tdhf response