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« Last post by **yannickf ** on* May 13, 2024, 04:43:58 PM* »
Dear Joan,

you can only use X2C with PCC and the derivatives of the unitary decoupling in the release version. So, you always get the full analytical derivative. DKH and BSS are not implemented as these are outdated theories and I did not want to implement it. You can simply use "$pnmr hfc-only" and get the results for the total HFC, the paramagnetic spin-orbit term, and the sum of the Fermi-contact and the spin-dipole term. Decoupling the Fermi-contact and the spin-dipole term is only possible in the non-relativistic limit (you can delete $rx2c before an mpshift run and use the non-relativistic EPR operators with the X2C-optimized density, i.e. without PCC). Below is a modified control:

`$title`

Cu(SMe)4 B3LYP ANO-DK3 Uncontracted HFC Term Decomposition Test 1

$symmetry c1

$coord file=coord

$optimize

internal off

redundant off

cartesian on

$atoms

basis =ANO-DK3

jbas =universal

$basis file=basis

$uhfmo_alpha file=alpha

$uhfmo_beta file=beta

$uhf

$alpha shells

a 1-66 ( 1 )

$beta shells

a 1-65 ( 1 )

$scfiterlimit 300

$scfdamp start=1.000 step=0.050 min=0.100

$scfdump

$scfdiis

$maxcor 500 MiB per_core

$energy file=energy

$grad file=gradient

$pop

$rx2c

$finnuc

$snso

$snsopara 0

$dft

functional b3-lyp

gridsize 5a

$scfconv 9

$scforbitalshift closedshell=.05

$ricore 500

$rij

$jbas file=auxbasis

$pnmr hfc-only

$rundimensions

natoms=21

$last step mpshift

PCC is always activated for NMR, EPR, and pNMR properties as results without PCC are typically wrong by orders of magnitude. With this settings you will get the following output for every nucleus.

1) Scalar-relativistic part, i.e. the Fermi-contact plus spin-dipole interaction (molecular frame)

2) The paramagnetic spin-orbit part (molecular frame)

3) Total HFC tensor in principal axis system

4) Eigenvectors for the principal axis system

Version 7.8 prints some more results and the Euler transformations.

Hope this helps.

Best wishes,

Yannick