Description section of the PSCTR file

This section starts with the line

Description

in the PSCTR file. It contains information, how pseudopotentials for each quantum number l are calculated. For each quantum number l more than one line, each corresponding to a different reference energy, can be supplied. The ordering must not be the same as in the V_RHFIN file, but for each valence orbital in the V_RHFIN file at least one corresponding line in the PSCTR file should exist. For conventional pseudopotentials (tag LULTRA=F, section 11.4.3) each line consists of one data set containing the following information

     0   .000     15  2.100
     L   EREF  ITYPE  RCUT

for ultrasoft pseudopotentials (tag LULTRA=T, section 11.4.3) each line must contain two data sets:

     2   .000      7  2.000    23  2.700
     L   EREF  ITYPE1 RCUT1 ITYPE2 RCUT2

The first data set controls the calculation of the norm conserving wave functions used for the augmentation part, the second one controls the possibly non normconserving part [18]. If LULTRA=T and if a specific l-pseudopotential should be normconserving (for instance we usually create a norm conserving $s$ pseudopotential and an ultrasoft d-pseudopotential for the transition metals), both datasets must be strictly similar, for instance:

     0   .000     15  2.100    15  2.100

In this case the augmentation charge is simply zero for the $s$ pseudopotential and a norm conserving $s$ PP is generated.

The first number in each line of the Description section is the l-quantum number, the second line gives the reference energy. If the reference energy is zero the pseudopotential is created for a bound state (i.e. the reference energy is similar to the corresponding eigenenergy of the valence wave function). If EREF is nonzero the pseudo wave function (and pseudopotential) for a non bound state is calculated [45]. ITYPE controls the type of the pseudopotential. The following values are possible to calculate norm conserving pseudo wave functions:

1	BHS
2	TM
3	VAN
6	XNC
7	RRKJ wave function possibly with node
15	RRKJ wave function strictly no node

For the BHS, VAN and XNC scheme the the energy derivative of $x_l(E)$ is fitted at the reference energy and no normconservation constraint is applied (for the non relativistic case a one to one relation ship between the logarithmic derivative and the normconservation constraint exists, this equation does not hold exactly for the scalar relativistic case). If the normconservation constraint should be used instead add 16 to these values. The RRKJ scheme without optimization (i.e. NMAX1=0, NMAX2=0) (section 11.4.10) might result in wave functions with a node close to $R=0$ this can be avoided setting ITYP to 15. Nevertheless nodes do not matter if factorized KB pseudopotential are generated.

Non norm conserving pseudo wave functions can be calculated adding 8 to the values given above i.e.:

9	BHS
10	TM
11	VAN
14	XNC
15	RRKJ wave function possibly with node
23	RRKJ wave function strictly no node

Extensive testing has been done only for ITYPE=15 and 23.