CASINO manual - Theory of Condensed Matter

Origin(s) for each potential (au)
0.0 0.0 0.0
Potential
... insert potential specification of appropriate type (see below)
END SET 1
... insert as many sets as required, consistently with ‘Number of sets’ above
END EXPOT
START EXPOT_WFN
Title
title
Number of sets
1
START SET 1
Periodicity [APERIODIC/PERIODIC]
PERIODIC
Type of orbitals
FOURIER
Direction [ISOTROPIC/A1/A2/A3/X/Y/Z/CUSTOM]
Z
[If CUSTOM then add direction vector after keyword e.g. CUSTOM 1.0 1.0 0.0]
Origin of orbitals
0.d0 0.d0 0.d0
Orbitals
... insert orbital specification of appropriate type (see below)
END SET 1
... insert as many sets as required, consistently with ‘Number of sets’ above
END EXPOT_WFN
Notes:
1. The Type of representation may take the following values for APERIODIC potentials (the
form of the corresponding Potential section is also given):
‘SQUARE’ Square well/barrier potentials centred at specified points. ‘Height’ can be set to
INF or -INF for generating infinite barriers or wells, respectively.
Potential
Width (au)
1.d0
Height (au)
-2.d0
‘LINEAR’ Linear potential corresponding to constant electric field E (= −dV/dx) passing
through 0 at specified point. Note that (i) it is assumed that the particles have charge −1
and (ii) the electrostatic energy of the nuclei is not calculated.
Potential
Electric Field (au)
1.d0
‘ANALYTIC’ Analytic aperiodic functions (for example, Gaussians, harmonic wells) centred
at specified points. Type of function to be specified in the Potential section:
Potential
Function type and defining parameters [(choose one; extra types definable)]
GAUSSIAN 1.d0 2.d0 0.d0 ! c,a,b in c*exp(-a*r^2)+b
HARMONIC 2.d0 0.d0 ! a,b in ar^2+b
SLAB 20.0 2.0
! Slab width, 2D r_s param.
‘GAUSSIAN’ Aperiodic Gaussian expansion.
Potential
Number of Gaussians
2
Coefficients and exponents
1.d0 6.d0
1.d0 2.d0
‘NUMERICAL’ Numerical representation on a grid.
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