$ECP
effective core pot's ECPLIB:ECPPAR
$ECP group (required if ECP=READ in $CONTRL)
This group lets you read in effective core potentials, for some or all
of the atoms in the molecule. You can use built in potentials for some of the
atoms if you like. This is a free format (positional) input group. *** Give a
card set -1-, -2-, and -3- for each atom *** -card 1- PNAME, PTYPE, IZCORE, LMAX
PNAME is a 8 character descriptive tag for this potential. If it is repeated for
a subsequent atom, no other information need be given on this card, and cards
-2- and -3- may also be skipped. The information will be copied from the first
atom by this PNAME. PTYPE = GEN a general potential should be read. = SBK
look up the Stevens/Basch/Krauss/Jasien/ Cundari potential for this type of atom.
= HW look up the Hay/Wadt built in potential for this type of atom. = NONE treat
all electrons on this atom. IZCORE is the number of core electrons to be removed.
LMAX is the maximum angular momentum occupied in the core orbitals being removed
(usually). Give IZCORE and LMAX only if PTYPE is GEN. *** For the first
occurence of PNAME, if PTYPE is GEN, *** *** then give cards -2- and -3-.
Otherwise go to -1-. *** *** Card sets -2- and -3- are repeated LMAX+1 times ***
The potential U(LMAX+1) is given first, followed by U(L)-U(LMAX+1), for
L=1,LMAX. -card 2- NGPOT NGPOT is the number of Gaussians in this part of the
local effective potential. -card 3- CLP,NLP,ZLP (repeat this card NGPOT times)
CLP is the coefficient of this Gaussian in the potential. NLP is the power of r
for this Gaussian. ZLP is the exponent of this Gaussian.
By far the easiest way to use the SBK potential for all atoms in the formic
acid molecule is to request ECP=SBK in $CONTRL. But the next page shows two
alternatives.
The first way is to look up the program's internally stored SBK potentials
one atom at a time:
$ECP
C-ECP SBK
H-ECP NONE
O-ECP SBK
O-ECP
H-ECP NONE
$END
The second oxygen duplicates the first, no core electrons are removed for
hydrogen. The order of the atoms must follow that generated by $DATA. Note PTYPE
allows you to type in one or more atoms explicitly, while using built in data
for some other atoms.
The second example reads all SBK potentials explicitly:
$ECP
C-ECP GEN 2 1
1 ----- CARBON U(P) -----
-0.89371 1 8.56468
2 ----- CARBON U(S-P) -----
1.92926 0 2.81497
14.88199 2 8.11296
H-ECP NONE
O-ECP GEN 2 1
1 ----- OXYGEN U(P) -----
-0.92550 1 16.11718
2 ----- OXYGEN U(S-P) -----
1.96069 0 5.05348
29.13442 2 15.95333
O-ECP
H-ECP NONE
$END
Again, the 2nd oxygen copies from the first. It is handy to use the rest of
card -2- as a descriptive comment.
As a final example, for antimony we have LMAX=3 (there are core d's). One
must first enter U(f), followed by
U(s)-U(f), U(p)-U(f), U(d)-U(f).