$ECP group            (required if PP=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.  Since the                      
input is a little tricky, it is good to look at the two                         
examples at the end of this group.                                              
*** Give a card set -1-, -2-, and -3- for each atom ***                         
-card 1-    PNAME, PTYPE, IZCORE, LMAX+1                                        
PNAME is a 8 character descriptive tag for this potential.                      
      If PNAME is repeated later, for the same type of                          
      element, the previously defined potential is copied                       
      to this atom.  No other information should be given                       
      on this card, and cards -2- and -3- must be skipped.                      
      Do not use this "copy" option when there is no core                       
      potential, instead type "NONE" over and over again.                       
PTYPE = GEN    a general potential should be read.                              
      = SBKJC  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.                           
       Obviously IZCORE must be an even number, or in other                     
       words, all core orbitals being removed must be                           
       completely occupied.                                                     
LMAX+1 is the one higher than the maximum angular momentum                      
       occupied in the core orbitals being removed:                             
          to remove s,p,d,f core orbitals  (LMAX=0,1,2,3)                       
          we use p,d,f,g core potentials (LMAX+1=1,2,3,4).                      
       LMAX+1 is not permitted to exceed 4.                                     
    *** Give IZCORE and LMAX only if PTYPE is GEN ***                           
*** For the first occurrence 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                         
    difference potentials U(L)-U(LMAX+1), for L=0,LMAX.                         
    Note that is a minus sign, not a hyphen!                                    
    The LMAX potential, and the differences of potentials                       
    are expanded by Gaussians, on these two cards.                              
-card 2-    NGPOT                                                               
NGPOT is the number of Gaussians in this part of the                            
      fit to 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, 0 <= NLP <= 2.                         
ZLP is the exponent of this Gaussian.                                           
Note that PTYPE lets you to type in one or more atoms                           
explicitly, while using built in data for other atoms.                          
By far the easiest way to use the SBKJC potential for all                       
atoms in the formic acid molecule is to request PP=SBKJC in                     
$CONTRL.  But here we show two alternatives.  Note that                         
both examples copy one oxygen potential to the other, and                       
both explicitly declare there is no potential on every                          
Assume that the atoms in $DATA are generated in the order                       
C, H, O, O, H.                                                                  
The first way is to look up the program's internally stored                     
SBKJC potentials one atom at a time:                                            
C-ECP SBKJC                                                                     
H-ECP NONE                                                                      
O-ECP SBKJC                                                                     
H-ECP NONE                                                                      
The second oxygen duplicates the first, no core electrons                       
are removed on hydrogen.  The order of the atoms must                           
follow that generated by $DATA.  All atoms must be given                        
here in $ECP, not just the symmetry unique atoms.                               
The second example reads all SBKJC potentials explicitly:                       
C-ECP GEN 2 1                                                                   
1      ----- CARBON U(P) -----                                                  
 -0.89371  1  8.56468                                                           
2      ----- CARBON U(S)-U(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)-U(P) -----                                             
  1.96069  0  5.05348                                                           
 29.13442  2 15.95333                                                           
H-ECP NONE                                                                      
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+1=3 (the core                     
3d is removed, so LMAX=2).  One must first enter U(f),                          
followed by U(s)-U(f), U(p)-U(f), U(d)-U(f).                                    

generated on 7/7/2017