$COMP group              (relevant for all SCFTYPs)
 
    This input defines the parameters for setting up a
composite thermochemical method, to evaluate heats of
formation.  Some literature methods are available, or you
can define your own.
 
RMETHD = hardwired composite methods
         G32CCSD is G3(MP2, CCSD(T))
         G4MP2 is G4(MP2)
         G4MP2-6X is G4(MP2)-6x
         CCCA-S4 is ccCA-S4
         CCCA-CCL is ccCA-CC(2,3)
No further input is required with these standard pathways.
 
GENERAL SETUP FOR OPTIMIZATIONS, HESSIAN, AND SINGLE POINT
ENERGIES:
 
IOP    = NUMBER OF OPTIMIZATIONS
IHS    = INDEX OF OPTIMIZATION USED FOR HESSIAN CALCULATION
IENE   = NUMBER OF SINGLE POINT ENERGY CALCULATIONS
         TOTAL # ENERGY CALCULATIONS = IOP + IENE
 
VARIOUS PARAMETERS FOR COMPOSITE METHOD:
 
CZPSCL = ZERO POINT ENERGY SCALING FACTOR
CENHLC = HIGHER LEVEL CORRECTION ENERGY
IENREF = REFERENCE ENERGY FOR COMPOSITE ENERGY CALCULATION
CXETH  = ADDED THERMAL ENERGY CORRECTION
CXHTH  = ADDED THERMAL ENTHALPY CORRECTION
CXGTH  = ADDED FREE ENERGY CORRECTION
CCXZPE = ADDED ZERO POINT ENERGY
CNUTRL = NEUTRAL ENERGY FOR HEATS OF FORMATION OF IONS AND
         RADICALS
CHEATS = ACCESSES ATOMIC ENERGIES FOR SPECIFIC COMPOSITE
         METHOD:
         G3MP2 is G3(MP2,CCSD(T)) atom energys
         CCCAS4 is ccCA-S4 atom energies
         CCCACCL is ccCA-CC(2,3) atom energies
CSCALE = PERFORMS SCALAR RELATIVISTIC CORRELATIONS (DK,
         ANESC, RESC)
CXTRAP = CBS EXTRAPOLATION TECHNIQUE
         S4 is a 2-POINT EXTRAPOLATION SCHEME
CGASES = GAS PHASE ENERGY VALUE FOR HEATS OF SOLVATION
         CALCULATION
 
ARRAYS FOR PARAMETERS USED FOR EACH COMPOSITE CALCULATION:
 
CDFTTP() = DFT FUNCTIONALS (DFTTYP VALUES)
ICMPLV() = MOLLER PLESSET ORDER NUMBER
CCCTYP() = COUPLED CLUSTER TYPE
CCITYP() = CONFIGURATION INTERACTION TYPE
CCSCF()  = SCF TYPE (RHF, ROHF, UHF)
      (DEFAULT VALUES IN SUBROUTINE 'CLRALL')
 
BASIS SET OPTION ARRAYS:
 
ICISPH() = ISPHER SPHERICAL HARMONICS
CGBASS() = GBASIS INTERNAL BASIS SETS
ICNGSS() = NGAUSS VALUES
ICNDFC() = NDFUNC (D POLARIZATION FUNCTION) VALUES
ICNFFC() = NFFUNC (F POLARIZATION FUNCTION) VALUES
ICNPFC() = NPFUNC (P POLARIZATION FUNCTION) VALUES
CDFFSP() = DIFFSP (SP DIFFUSE FUNCTION) OPTION
CDIFFS() = DIFFS  (S DIFFUSE FUNCTION) OPTION
 
Additional calculation controls:
 
CETOT()  = ADDED ENERGY VALUES, ADD VALUE TO SKIP A
           CALCULATION (CETOT(1) SKIPS CALCULATION 1)
ICNACR() = NACORE (# ALPHA CORE ELECTRONS)
ICNBCR() = NBCORE (# BETA CORE ELECTRONS)
ICNCOR() = NCORE(NCCFZC)(# CORE ELECTRONS)
IDOPCM() = PCM CONTROL (0 = OFF, 1 = ON)
ICNDER() = MP2 GRADIENT CONTROL, FOR OPTIMIZATIONS
           (0=OFF, 1=ON)
IEXTRP() = SELECTS CETOT() ENERGIES FOR CBS EXTRAPOLATION
CESCF()  = OBTAINS REFERENCE ENERGY FOR CBS EXTRAPOLATION
CECOR()  = OBTAINS CORRELATION ENERGY FOR CBS EXTRAPOLATION
 
ENERGY CORRECTION CALCULATION (ICENCA - ICENCB):
 
ICENCA() = HIGHER LEVEL CALCULATION
ICENCB() = LOWER LEVEL CALCULATION
 
There are three ways to carry out a G3(MP2,CCSD(T))
calculation, which serve to illustrate the above:
 
a) select RUNTYP=G3MP2
b) select RUNTYP=COMP and $COMP's RMETHD=G32CCSD
c) select RUNTYP=COMP and explicitly define it:
 
$COMP
  iop=2, ihs=1, iene=3, icalc=2, ienref=5,
  cenhlc=-0.009170, czpscl=0.8929, cheats=g3mp2,
  icmplv(2)=2,
  icmplv(4)=2,
  icmplv(5)=2,
  ccctyp(3)=ccsd(t),
  icisph(4)=1,
  cgbass(1)=n31,n31,n31,g3l,n31,
  icngss(1)=6,6,6,0,6,
  icndfc(1)=1,1,1,0,1,
  icnacr(2)=0,
  icnbcr(2)=0,
  icnder(2)=1,
  icenca(1)=3,4,
  icencb(1)=5,5
 $END
 
In case of failures when the program shifts basis sets, try
running without point group symmetry: NOSYM=1 in $CONTRL.