$TRUDGE group            (required for RUNTYP=TRUDGE)                           
    This group defines the parameters for a non-gradient                        
optimization of exponents or the geometry.  The TRUDGE                          
package is a modified version of the same code from Michel                      
Dupuis' HONDO 7.0 system, origially written by H.F.King.                        
Presently the program allows for the optimization of 10                         
    Exponent optimization works only for uncontracted                           
primitives, without enforcing any constraints.  Two                             
non-symmetry equivalent H atoms would have their p                              
function exponents optimized separately, and so would two                       
symmetry equivalent atoms!  A clear case of GIGO.                               
    Geometry optimization works only in HINT internal                           
coordinates (see $CONTRL and $DATA inputs).  The total                          
energy of all types of SCF wavefunctions can be optimized,                      
although this would be extremely stupid as gradient                             
methods are far more efficient.  The main utility is for                        
open shell MP2 or CI geometry optimizations, which may                          
not be done in any other way with GAMESS.  If your run                          
requires NOSYM=1 in $CONTRL, you must be sure to use only                       
C1 symmetry in the $DATA input.                                                 
OPTMIZ = a flag to select optimization of either geometry                       
         or exponents of primitive gaussian functions.                          
       = BASIS    for basis set optimization.                                   
       = GEOMETRY for geometry optimization (default).                          
         This means minima search only, there is no saddle                      
         point capability.                                                      
NPAR   = number of parameters to be optimized.                                  
IEX    = defines the parameters to be optimized.                                
         If OPTMIZ=BASIS, IEX declares the serial number                        
    of the Gaussian primitives for which the exponents                          
    will be optimized.                                                          
         If OPTMIZ=GEOMETRY, IEX define the pointers to                         
    the HINT internal coordinates which will be optimized.                      
    (Note that not all internal coordinates have to be                          
    optimized.) The pointers to the internal coordinates                        
    are defined as:  (the number of atom on the input                           
    list)*10 + (the number of internal coordinate for that                      
    atom).  For each atom, the HINT internal coordinates                        
    are numbered as 1, 2, and 3 for BOND, ALPHA, and BETA,                      
P  =  Defines the initial values of the parameters to be                        
      optimized.  You can use this to reset values given                        
      in $DATA.  If omitted, the $DATA values are used.                         
      If given here, geometric data must be in Angstroms                        
      and degrees.                                                              
A complete example is a TCSCF multireference 6-31G                              
geometry optimization for methylene,                                            
 $CONTRL SCFTYP=GVB CITYP=GUGA RUNTYP=TRUDGE                                    
         COORD=HINT $END                                                        
 $BASIS  GBASIS=N31 NGAUSS=6 $END                                               
Methylene TCSCF+CISD geometry optimization                                      
Cnv 2                                                                           
C    6.     LC  0.00  0.0  0.00  -  O  K                                        
H    1.    PCC  1.00  53.  0.00  +  O  K  I                                     
 $SCF    NCO=3 NPAIR=1 $END                                                     
 $TRUDGE OPTMIZ=GEOMETRY  NPAR=2                                                
         IEX(1)=21,22   P(1)=1.08 $END                                          
 $CIDRT  GROUP=C2V SOCI=.TRUE. NFZC=1 NDOC=3 NVAL=1                             
         NEXT=-1 $END                                                           
using GVB-PP(1), or TCSCF orbitals in the CI.  The starting                     
bond length is reset to 1.09, while the initial angle will                      
be 106 (twice 53).  Result after 17 steps is R=1.1283056,                       
half-angle=51.83377, with a CI energy of -38.9407538472                         
    Note that you may optimize the geometry for an excited                      
CI state, just specify                                                          
          $GUGDIA   NSTATE=5  $END                                              
          $GUGDM    IROOT=3   $END                                              
to find the equilibrium geometry of the third state (of                         
five total states) of the symmetry implied by your $CIDRT.                      

generated on 7/7/2017