SCM: ADF Property Programs

EPRGTENSOR

Subkey EprGTensor

invokes the calculation of the EPR (or ESR) g-tensor and its contributions.

The key is a block type subkey, and (most of) the arguments are not really required. Those arguments are (abbreviations in brackets):

EprGTensor
   EPRXC {X-ALP NONE}
   XCCutOff (XCCUT)
   KinCorrection (KINCORR)
   Skip
SubEnd

Disabled arguments include TestPot and TestPar. The other keywords in detail:

EPRXC
regulates which XC potential to use for the exchange in the effective ESR potential (Georg Schreckenbach's Ph.D. thesis, p. 124).
Note that this does not influence the XC potential that is used elsewhere in the calculation.
Currently implemented are the following two arguments:
X-Alpha (X-ALP) and NONE
In addition, it is possible to specify the X-alpha parameter to be used as a non-negative real number after the keyword. The default for the whole keyword is:

 EPRXC X-Alpha 0.7

XCCutOff
A numerical cutoff to be used with the EPR exchange potential. It avoids numerical instabilities, but has no influence on the results otherwise. The default turns out to be sensitive, and should not be changed (it depends on the number of integration points and the number of electrons). Alternatively, one can specify a real number CUTFF: the EPR exchange potential is set to zero if its value is smaller then 10**-CUTFF in the given integration point.
KinCorrection
This keywords includes or excludes the use of the isotropic kinetic energy to the g-tensor. Arguments are ON (default) and OFF.
Skip
This key allows one to exclude various contributions from the calculation of the g-tensor that might be useful to see their respective importance (see, e.g., the EPR paper, tables 7 and 8).
Possible arguments are (any of)

 NucDerivative (NUCDER)
 CoreDerivative (COREDER)
 ValDerivative (VALDER)
 XCDerivative (XCDER)
 KinCorrection (KINCORR)

Specifying these arguments excludes the derivative of the nuclear, core electronic, valence electronic, or exchange potentials (arguments NUCDER, COREDER, VALDER, or XCDER, respectively) from the effective potential to be used for the g-tensor. Specifying XCDER here is equivalent to the argument NONE of the keyword EPRXC. Finally, Skip KinCorr excludes the kinetic energy correction from the g-tensor, and is equivalent to the keyword KinCorr OFF.

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