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developers:pseudos:psp45_format [2015/02/25 14:27] – created Matteo Giantomassidevelopers:pseudos:psp45_format [2020/08/10 20:07] (current) – Xavier Gonze
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 +==== This file contains information about formats of pspcod=4 and pspcod=5 pseudopotentials. ====
 +
 +Pspcod=4 corresponds to the case of Teter pseudopotentials
 +generated in Louvain-La-Neuve using the code ATOM. Pspcod=5 corresponds
 +to "Phoney" pseudopotentials built on a Hamman grid. At this stage (22 July 1998) 
 +it is possible to treat these pseudopotentials (in the version 1.5 and later).  
 +However, one has to be careful about the formats of these pseudopotentials. 
 +Indeed, to be read by the ABINIT code, they have to be
 +slightly modified. Let's take examples to explain these modifications:
 +
 +A. pspcod = 4 case (Teter pseudopotentials). The example corresponds to Lead.
 +
 +1. OLD HEADER
 +
 +  (Xe+4f14)+6s1.8 5d10 6p0.2 5f0.05;rcs=rcd=2.0(exnc11),rcp=2.0(26),rcf=1.3(11) no chem-hard; ecut 19/25
 +    82.00000  14.00000  0.000000000000000000E+00      z,zion,etot(wrong)
 +           4         3         2      2001            iexc,ipsp,lmax-1,ngrid
 +    .000   .000000000000000000E+00   .000000000000000000E+00 rchrg,fchrg,qchrg
 +   2.00426660272461010 2.00426660272461010 2.00426660272461010 1.29915156996312131
 +   2 2 2 0
 +
 +2. NEW HEADER (READABLE BY ABINIT)
 +
 +  (Xe+4f14)+6s1.8 5d10 6p0.2 5f0.05;rcs=rcd=2.0(exnc11),rcp=2.0(26),rcf=1.3(11) no chem-hard; ecut 19/25
 +    82.00000  14.00000  960808                 zatom,zion,pspdat
 +    4         3         3   3      2001    0  pspcod,pspxc,lmax,lloc,mmax,r2well
 +    0  0  0   2    2.00426660272461010          l,e99.0,e99.9,nproj,rcpsp
 +    .000 .000 .000 .000                         rms,ekb1,ekb2,epsatm
 +    1  0  0   2    2.00426660272461010          l,e99.0,e99.9,nproj,rcpsp
 +    .000 .000 .000 .000                         rms,ekb1,ekb2,epsatm
 +    2  0  0   2    2.00426660272461010          l,e99.0,e99.9,nproj,rcpsp
 +    .000 .000 .000 .000                         rms,ekb1,ekb2,epsatm
 +    3  0  0   0    1.29915156996312131          l,e99.0,e99.9,nproj,rcpsp
 +    .000 .000 .000 .000                         rms,ekb1,ekb2,epsatm
 +    .000   .000   .000                          rchrg,fchrg,qchrg
 +
 + This header corresponds exactly to these of the TM pseudoptentials (pspcod=1).
 + In addition, in the new form of the Teter pseudopotentials, one indicates the
 + number of angular momentum before each set of data corresponding to the
 + considered angular momentum. This allows a clearer pseudopotential file.
 +
 +--------------------------------------------------------------------------------
 +
 +B. pspcod = 5 case ("Phoney" pseudopotentials).
 +   The example corresponds to Oxygen.
 +
 +1. OLD HEADER
 +
 +Compromise psp for oxygen with rc=1.5 ec=25 double reference
 +   8.00000000000000000       6.00000000000000000      -15.6648128583845843
 +           4           2           0         600
 +  0.999999999999999955E-06  0.307523885541775704E-01
 +   1.49157651759552068       1.49157651759552068
 +           2           0
 +
 +2. NEW HEADER  (READABLE BY ABINIT)
 +
 +Compromise psp for oxygen with rc=1.5 ec=25 double reference
 +   8.000       6.000      980710     zatom,zion,pspdat
 +   5   3   1   1   600     0         pspcod,pspxc,lmax,lloc,mmax,r2well
 +   0.999999999999999955E-06  0.307523885541775704E-01  r1,al
 +   0  0  0   2     1.49157651759552068               l,e99.0,e99.9,nproj,rcpsp
 +   0  0  0   0                                       rms,ekb1,ekb2,epsatm
 +   1  0  0   0      1.49157651759552068              l,e99.0,e99.9,nproj,rcpsp
 +   0  0  0   0                                       rms,ekb1,ekb2,epsatm
 +   0  0  0                                           rchrg,fchrg,qchrg
 +
 +
 +
 +Note that this header is almost the same as for the pspcod=1 and pspcod=4 case.
 +The only difference lies in the presence of "r1" and "al" parameters (defining
 +the Hamman grid). Here also, we indicate in addition the number of each angular
 +momentum before the set of data corresponding to the considered angular momentum.
 +
 +-------------------------------------------------------------------------------
 +
 +Inside ABINIT, a pseudopotential with format 4 will be treated by
 +the routine psp1in.f, that calls psp1lo.f (local part),
 +psp1nl.f (non-local part), and psp1cc (core correction).
 +
 +As a matter of numerical accuracy, note that the integral
 +of (V(r)+Zion/r) r^2 in psp1lo.f is performed from 0 to the highest
 +allowed radius (usually about 100 a.u.), without cut-off.
 +V(r)+Zion/r should tend rapidly to zero
 +for large radii (beyond 5 a.u.), but this correct behaviour will
 +not be enforced by psp1lo . If the tail of V(r) is inaccurate
 +(i.e. if the pseudopotential is in single precision), there
 +will be large inaccuracies in the integral, because of the r^2 factor.
 +
 +By contrast, a pseudopotential with format 5 will be treated by
 +the routine psp5in.f, that calls psp5lo.f (local part),
 +psp5nl.f (non-local part), and psp5cc (core correction).
 +
 +The integral of (V(r)+Zion/r) r^2 in psp5lo.f is performed
 +from 0 to the highest allowed radius (usually about 100 a.u.),
 +except that beyond 20 a.u. no value of abs(V(r)) larger
 +than 2.0d-8 is tolerated. This will allow to cut off spurious
 +behaviour of pseudopotential whose data file is written in single precision.