$EFRAG group                                (optional)                          
   The Effective Fragment Potential (EFP) is a potential                        
extracted from rigorous quantum mechanics, permitting the                       
treatment of solvent molecules (or other types of                               
subsystems) with a potential.  There are two models, EFP1                       
and EFP2, with more accurate physics in the latter.  For                        
more information, see chapter 4 of this manual.                                 
   EFP1 calculations are typically limited to a QM system                       
with water molecules, the latter modeled by RHF-based or                        
DFT-based potentials which are built into the program.  The                     
following EFP1/QM calculations are possible:                                    
    QM/EFP1                       method1  method2  SCF                         
    RHF (and DFT)       gradient                     x                          
    UHF (and DFT)       gradient                     x                          
    ROHF(and DFT)       gradient                     x                          
    MP2(RHF/UHF/ROHF)   gradient    x        x                                  
    CCSD                energy      x        x                                  
    CCSD(T)             energy      x                                           
    CR-CCL              energy      x                                           
    EOM-CCSD            energy      x        x                                  
    CR-EOML             energy      x                                           
    CITYP=CIS (only)    gradient    x        x                                  
    TDDFT(RHF)          gradient    x        x                                  
    GVB                 gradient                     x                          
    MCSCF               gradient                     x                          
Here, SCF means the QM calculation and the EFP particle's                       
polarizability terms are made fully self-consistent.                            
Otherwise, the QM density felt by the EFP particles is that                     
of the reference (ground) state, termed "method 1".  A more                     
accurate and detailed energy calculation is possible when                       
the QM's density is available for a specific correlation                        
treatment and/or a specific excited state.  Such "method 2"                     
calculations are available only for RUNTYP=QMEFPEA.  The                        
"method 1" calculations can be used for any relevant run                        
type using the energy or analytic nuclear gradients, as                         
indicated.  For example, after MP2 geometry optimization,                       
numerical differentiation can produce solvated MP2-level                        
   EFP2 calculations should use COORD=FRAGONLY at the                           
present time, as the QM/EFP2 interaction terms are                              
currently under active development.  The programming for                        
EFP2/EFP2 interactions is completed.  See RUNTYP=MAKEFP to                      
create EFP2 potentials.                                                         
   In most cases, the entire EFP1, QM/EFP1, or EFP2 system                      
can be embedded in a PCM continuum (see $PCM).                                  
   This group gives the name and position of one or more                        
effective fragment potentials.  It consists of a series of                      
free format card images, which may not be combined onto a                       
single line!  The position of a fragment is defined by                          
giving any three points within the fragment, relative to                        
the ab initio system defined in $DATA, since the effective                      
fragments have a frozen internal geometry.  All other atoms                     
within the fragment are defined by information in the                           
$FRAGNAME input group.                                                          
-1-   a line containing one or more of these options:                           
If you choose more options than are able to be fit on a                         
single 80 character line, type an > character to continue                       
onto the next line.                                                             
If you do not choose any of these options, input a blank                        
line to accept defaults.                                                        
     COORD   =CART     selects use of Cartesians coords                         
                       to define the fragment position at                       
                       line -3-.  (default)                                     
             =INT      selects use of Z-matrix internal                         
                       coordinates at line -3-.                                 
     POLMETHD=SCF      indicates the induced dipole for                         
                       each fragment due to the ab initio                       
                       electric field and other fragment                        
                       fields is updated only once during                       
                       each SCF iteration.                                      
             =FRGSCF   requests microiterations during                          
                       each SCF iteration to make induced                       
                       dipoles due to ab initio and other                       
                       fragment fields self consistent                          
                       among the fragments.  (default)                          
                       Both methods converge to the same                        
                       dipolar interaction.                                     
     POSITION=OPTIMIZE Allows full optimization within the                      
                       ab initio part, and optimization of                      
                       the rotational and translational                         
                       motions of each fragment. (default)                      
             =FIXED    Allows full optimization of the                          
                       ab initio system, but freezes the                        
                       position of the fragments.  This                         
                       makes sense only with two or more                        
                       fragments, as what is frozen is the                      
                       fragments' relative orientation.                         
                       FIXED may be used with RUNTYP being                      
                       OPTIMIZE, SADPOINT, HESSIAN and IRC.                     
             =EFOPT    the same as OPTIMIZE, but if the                         
                       fragment gradient is large, up to                        
                       5 geometry steps in which only the                       
                       fragments move may occur, before                         
                       the geometry of the ab initio piece                      
                       is relaxed.  This may save time by                       
                       reusing the two electron integrals                       
                       for the ab initio system.                                
     NBUFFMO = n       First n orbitals in the MO matrix                        
                       are deemed to belong to the QM/MM                        
                       buffer and will be excluded from                         
                       the interaction with the EFP region.                     
                       This makes sense only if these first                     
                       MOs are frozen via the $MOFRZ.                           
The next few inputs apply periodic boundary conditions,                         
which is only possible if the system contains only EFP                          
particles, with no ab initio atoms.  The default is to use                      
the minimum image convention, for all terms in the                              
potentials, but see also the $EWALD input group in order to                     
perform the long range electrostatic interactions in a more                     
accurate manner.  You may choose no more than one of the                        
possible sets of cutoffs, with the switching function                           
SWR1/SWR2 being the most physically reasonable.                                 
     XBOX, YBOX, ZBOX  = dimensions of the periodic box,                        
                         which must be given in Angstroms.                      
                         If these sizes are omitted, the                        
                         simulation is an isolated cluster.                     
     SWR1, SWR2        = distance cutoffs for the switching                     
                         function that gradually drops the                      
                         interactions from full strength at                     
                         SWR1 to zero at SWR2.  Choose                          
                         SWR2 <= min(XBOX/2,YBOX/2,ZBOX/2)                      
                         and SWR1 <= SWR2 (typically 80%),                      
                         to cut off interactions within a                       
                         single box.  In Angstrom                               
     RCUT                a radial cutoff, implemented as a                      
                         step function, which should be                         
                         chosen like SWR2.  In Angstrom                         
     XCUT, YCUT, ZCUT  = cutoffs (as step functions) beyond                     
                         which effective fragment potential                     
                         interactions are not computed,                         
                         XCUT <= XBOX/2, etc.  Angstroms                        
For a simulation of 64 CCl4 molecules, PBC input might be                       
    xbox=21.77 ybox=21.77 zbox=21.77 swr1=8.0 swr2=10.0                         
Box sizes are typically chosen to give a correct value for                      
the density of the system.                                                      
The following turn off selected terms in the potentials,                        
even if data for the term is found in the various $FRAGNAME                     
input groups.  These keywords are standalone strings,                           
without a value assigned to them.  They allow data from                         
potentials generated by MAKEFP runs to be kept in the                           
$FRAGNAME, for possible future use.  The first two are of                       
interest in production runs, while the others are primarily                     
meant for debugging purposes, as the latter terms are                           
normally quite large.                                                           
     NOCHTR    = switch off charge transfer in EFP2                             
     NODISP    = switch off dispersion in EFP2                                  
     NOEXREP   = switch off exchange repulsion (EFP1/EFP2)                      
     NOPOL     = switch off polarization (implies NOPSCR)                       
     NOPSCR    = switch off polarization screening, only                        
The following parameters are related to screening of some                       
terms in the potentials, when fragments are at close                            
distances.  Note that they are relevant only to EFP2 runs.                      
Prior to May 2009, the defaults were                                            
      ISCRELEC=0 ISCRPOL=0 ISCRDISP=0                                           
at which time the defaults were changed to                                      
      ISCRELEC=0 ISCRPOL=1 ISCRDISP=1                                           
If you need to reproduce results or continue an ongoing set                     
of computations, simply input the old defaults.                                 
   ISCRELEC =   fragment-fragment electrostatic screening,                      
                a correction for "charge penetration":                          
                   E(elec) = E(multipoles) + E(chg.pen.)                        
            = 0 damping by various formulae is controlled                       
                by SCREEN1, SCREEN2, or SCREEN3 input                           
                sections in the $FRAGNAME input(s).  If                         
                none are found, there will be no charge                         
                penetration screening of electrostatics.                        
            = 1 use an overlap based damping correction                         
                   E(chg.pen.)= -2(S**2/R)/sqrt(-2ln|S|)                        
                to the classical multipole energy.  Since                       
                the overlap integrals used here, as well as                     
                in ISCRDISP must be evaluated as part of                        
                the exchange repulsion energy, there is                         
                essentially no overhead for selecting this.                     
   ISCRPOL  =   fragment-fragment polarization screening.                       
            = 0 damping is controlled by POLSCR sections in                     
                the $FRAGNAME inputs.  If not found, there                      
                will be no screening.  If POLSCR is found,                      
                you must also use ISCRELEC=0 and SCREEN3.                       
            = 1 damping will use a Tang-Toennis style                           
                Gaussian formula,                                               
                where the default value of a=0.6.  In order                     
                to change the 'a' parameter, give                               
                in the $FRAGNAME input.  A smaller value                        
                may be useful for ionic EFPs.  (default)                        
   ISCRDISP =   fragment-fragment dispersion screening                          
            = 0 Use Tang-Toennies damping, with a fixed                         
                parameter a=1.5.                                                
            = 1 use an overlap based damping factor,                            
                instead.  There is no parameterization, so                      
                there's no other input.  (default)                              
It is possible to choose ISCRELEC, ISCRPOL, and ISCRDISP                        
independently, as they apply to distinct parts of the                           
fragment-fragment effective potential, and apart from                           
POLSCR/SCREEN3, are independently implemented.                                  
   FRCPNT      this keyword activates decomposing and                           
               printing the forces at the desired points in                     
               the EFP fragments, in additional to the                          
               traditional summing of the forces at the                         
               fragments' center-of-masses. This is useful                      
               for coarse graining the EFP data.  If this                       
               option is selected, FORCE POINT section(s)                       
               must be given in the $FRAGNAME input(s).                         
The following keywords are for use with the EFP2-AI (a.k.a.                     
EFP2-QM) dispersion calculation, that is, the calculation                       
of the dispersion energy in a mixed system containing one                       
or more EFP2 fragment(s) and a molecule modeled with a                          
fully ab initio method (e.g. Hartree-Fock).                                     
   QMDISP      specify whether to perform the calculation                       
               of EFP2-AI dispersion                                            
          = 0  do not calculate dispersion, even if both                        
               an EFP2 fragment and an ab initio part are                       
               present (default)                                                
          = 1  perform the EFP2-AI dispersion calculation                       
   ISCRQMDS    specify type of screening to use with                            
               EFP2-AI damping                                                  
          =-1  turn off damping (for debugging or benchmark                     
               comparison purposes)                                             
          = 0  use Tang-Toennies damping, with a fixed                          
               parameter a=1.5                                                  
          = 1  use a parameter-free, overlap-based damping                      
               factor, 1-S**2(1-2ln|S|+2ln**2|S|) (default)                     
   NODSGRD     skip calculation of the EFP2-AI dispersion                       
               gradient, even if a gradient calculation is                      
               specified with RUNTYP=GRADIENT                                   
Note that localized orbitals are necessary for the                              
dispersion energy calculation. Boys localization will be                        
performed by default if QMDISP=1 is specified, with no                          
additional input keywords necessary. An alternate                               
localization method may be specified using the LOCAL                            
keyword in $CONTRL.                                                             
   NIDISP7     skip computating the 7th power dispersion.                       
-2-  FRAGNAME=XXX                                                               
XXX is the name of the fragment whose coordinates are to be                     
given next, and whose potential may also be in the input                        
stream, as $XXX groups.  XXX may not exceed 6 characters.                       
Below, the actual $XXX groups are referred to generically                       
as $FRAGNAME.  Specific examples of $FRAGNAME are $C6H6,                        
$BENZEN, $DMSO, ...                                                             
All information defining the EFP2-type fragment potential                       
is given in its $FRAGNAME.  A few standard EFP2 potentials                      
are provided: see ~/gamess/auxdata/EFP.  These are used by                      
placing the desired file(s) into your input.                                    
Two different EFP1-type water potentials are internally                         
stored.  FRAGNAME=H2ORHF will select a water potential                          
developed at the RHF/DZP level, while FRAGNAME=H2ODFT will                      
select a potential corresponding to B3LYP/DZP (see $BASIS                       
for the precise meaning of DZP).  If you choose either of                       
these internally stored potentials, you need not give any                       
further input to define them.                                                   
Since the EFP model consists of distributed multipoles and                      
distributed polarizabilities, it is trivial to map some of                      
the literature's simplified water potentials onto the EFP1                      
programming.  For example, the octupole expansions used in                      
EFP can be truncated to point charges (monopole term).  So,                     
FRAGNAME may also be any of the following water models:                         
     SPC, SPCE, TIP5P, TIP5PE, or POL5P                                         
Their EFP/EFP repulsion term is a typical 6-12 Lennard-                         
Jones form.  Repulsion between the QM and EFP particles                         
follows the EFP1 style, if any QM atoms are input.                              
-3-   NAME, X, Y, Z                           (COORD=CART)                      
      NAME, I, DISTANCE, J, BEND, K, TORSION  (COORD=INT)                       
NAME     = the name of a fragment point.  The name used                         
           here must match one of the points in $FRAGNAME.                      
           For the internally stored H2ORHF and H2ODFT                          
           potential, the atom names are O1, H2, and H3.                        
X, Y, Z  = Cartesian coordinates defining the position of                       
           this fragment point RELATIVE TO THE COORDINATE                       
           ORIGIN used in $DATA.  The choice of units is                        
           controlled by UNITS in $CONTRL.                                      
I, DISTANCE, J, BEND, K, TORSION = the usual Z-matrix                           
           connectivity internal coordinate definition.                         
           The atoms I, J, K must be atoms in the ab                            
           initio system from in $DATA, or fragment points                      
           already defined in the current fragment or                           
           previously defined fragments.                                        
If COORD=INT, line -3- must be given a total of three times                     
to define this fragment's position.                                             
If COORD=CART, line -3- must be given three times, which is                     
sufficient to orient the rigid EFP particle.  However, it                       
is good form to read in any remaining nuclei in the EFP,                        
for example all 12 atoms in a benzene EFP, although only                        
the first three lines determine the entire EFP's position,                      
whenever you have the data for the extra nuclei.                                
Repeat lines -2- and -3- to enter as many fragments as you                      
desire, and then end the group with a $END line.                                
Note that it is quite typical to repeat the same fragment                       
name at line -2-, to use the same type of fragment system                       
at many different positions.                                                    
        * * * * * * * * * * * * * * * * * * * * *                               
        For tips on effective fragment potentials                               
          see the 'further information' section                                 
        * * * * * * * * * * * * * * * * * * * * *                               

generated on 7/7/2017