$DATA group                                    (required)
$DATAS group  (if NESC chosen, for small component basis)
$DATAL group  (if NESC chosen, for large component basis)
 
    This group describes the global molecular data such as
point group symmetry, nuclear coordinates, and possibly
the basis set.  It consists of a series of free format
card images. See $RELWFN for more information on large and
small component basis sets.  The input structure of $DATAS
and $DATAL is identical to the COORD=UNIQUE $DATA input.
 
----------------------------------------------------------
 
-1-   TITLE     a single descriptive title card.
 
----------------------------------------------------------
 
-2-   GROUP, NAXIS
 
GROUP is the Schoenflies symbol of the symmetry group,
you may choose from
    C1, Cs, Ci, Cn, S2n, Cnh, Cnv, Dn, Dnh, Dnd,
    T, Th, Td, O, Oh.
 
NAXIS is the order of the highest rotation axis, and
must be given when the name of the group contains an N.
For example, "Cnv 2" is C2v.  "S2n 3" means S6.  Use of
NAXIS up to 8 is supported in each axial groups.
 
For linear molecules, choose either Cnv or Dnh, and enter
NAXIS as 4.  Enter atoms as Dnh with NAXIS=2.  If the
electronic state of either is degenerate, check the note
about the effect of symmetry in the electronic state
in the SCF section of REFS.DOC.
 
----------------------------------------------------------
 
    In order to use GAMESS effectively, you must be able
to recognize the point group name for your molecule.  This
presupposes a knowledge of group theory at about the level
of Cotton's "Group Theory", Chapter 3.
 
    Armed with only the name of the group, GAMESS is able
to exploit the molecular symmetry throughout almost all of
the program, and thus save a great deal of computer time.
GAMESS does not require that you know very much else about
group theory, although a deeper knowledge (character
tables, irreducible representations, term symbols, and so
on) is useful when dealing with the more sophisticated
wavefunctions.
 
Cards -3- and -4- are quite complicated, and are rarely
given.  A *SINGLE* blank card may replace both cards -3-
and -4-, to select the 'master frame', which is defined on
the next page.   If you choose to enter a blank line, skip
to one of the -5- input sequences.
 
                       Note!
If the point group is C1 (no symmetry), skip over cards
-3- and -4- (which means no blank card).
 
----------------------------------------------------------
 
-3-  X1, Y1, Z1, X2, Y2, Z2
 
For C1 group, there is no card -3- or -4-.
For CI group, give one point, the center of inversion.
For CS group, any two points in the symmetry plane.
For axial groups, any two points on the principal axis.
For tetrahedral groups, any two points on a two-fold axis.
For octahedral groups, any two points on a four-fold axis.
 
----------------------------------------------------------
 
-4-  X3, Y3, Z3, DIRECT
 
third point, and a directional parameter.
For CS group, one point of the symmetry plane,
              noncollinear with points 1 and 2.
For CI group, there is no card -4-.
 
For other groups, a generator sigma-v plane (if any) is
the (x,z) plane of the local frame (CNV point groups).
 
A generator sigma-h plane (if any) is the (x,y) plane of
the local frame (CNH and dihedral groups).
 
A generator C2 axis (if any) is the x-axis of the local
frame (dihedral groups).
 
The perpendicular to the principal axis passing through
the third point defines a direction called D1.  If
DIRECT='PARALLEL', the x-axis of the local frame coincides
with the direction D1.  If DIRECT='NORMAL', the x-axis of
the local frame is the common perpendicular to D1 and the
principal axis, passing through the intersection point of
these two lines.  Thus D1 coincides in this case with the
negative y axis.
 
----------------------------------------------------------
 
    The 'master frame' is just a standard orientation for
the molecule.  By default, the 'master frame' assumes that
    1.   z is the principal rotation axis (if any),
    2.   x is a perpendicular two-fold axis (if any),
    3.  xz is the sigma-v plane (if any), and
    4.  xy is the sigma-h plane (if any).
Use the lowest number rule that applies to your molecule.
 
        Some examples of these rules:
Ammonia (C3v): the unique H lies in the XZ plane (R1,R3).
Ethane (D3d): the unique H lies in the YZ plane (R1,R2).
Methane (Td): the H lies in the XYZ direction (R2).  Since
         there is more than one 3-fold, R1 does not apply.
HP=O (Cs): the mirror plane is the XY plane (R4).
 
In general, it is a poor idea to try to reorient the
molecule.  Certain sections of the program, such as the
orbital symmetry assignment, do not know how to deal with
cases where the 'master frame' has been changed.
 
Linear molecules (C4v or D4h) must lie along the z axis,
so do not try to reorient linear molecules.
 
You can use EXETYP=CHECK to quickly find what atoms are
generated, and in what order.  This is typically necessary
in order to use the general $ZMAT coordinates.
 
                     * * * *
 
Depending on your choice for COORD in $CONTROL,
 
    if COORD=UNIQUE, follow card sequence U
    if COORD=HINT,   follow card sequence U
    if COORD=CART,   follow card sequence C
    if COORD=ZMT,    follow card sequence G
    if COORD=ZMTMPC, follow card sequence M
 
Card sequence U is the only one which allows you to define
a completely general basis here in $DATA.
 
Recall that UNIT in $CONTRL determines the distance units.
 
----------------------------------------------------------
 
-5U-   Atom input.  Only the symmetry unique atoms are
input, GAMESS will generate the symmetry equivalent atoms
according to the point group selected above.
 
   if COORD=UNIQUE   NAME, ZNUC, X, Y, Z
   ***************
 
NAME  = 10 character atomic name, used only for printout.
        Thus you can enter H or Hydrogen, or whatever.
ZNUC  = nuclear charge.  It is the nuclear charge which
        actually defines the atom's identity.
X,Y,Z = Cartesian coordinates.
 
   if COORD=HINT
   *************
 
   NAME,ZNUC,CONX,R,ALPHA,BETA,SIGN,POINT1,POINT2,POINT3
 
NAME = 10 character atomic name (used only for print out).
ZNUC = nuclear charge.
CONX = connection type, choose from
  'LC'   linear conn.               'CCPA' central conn.
  'PCC'  planar central conn.              with polar atom
  'NPCC' non-planar central conn.   'TCT'  terminal conn.
  'PTC'  planar terminal conn.             with torsion
R    = connection distance.
ALPHA= first connection angle
BETA = second connection angle
SIGN = connection sign, '+' or '-'
POINT1, POINT2, POINT3 =
     connection points, a serial number of a previously
     input atom, or one of 4 standard points: O,I,J,K
     (origin and unit points on axes of master frame).
     defaults:  POINT1='O', POINT2='I', POINT3='J'
 
ref- R.L. Hilderbrandt, J.Chem.Phys. 51, 1654 (1969).
You cannot understand HINT input without reading this.
 
Note that if ZNUC is negative, the internally stored
basis for ABS(ZNUC) is placed on this center, but the
calculation uses ZNUC=0 after this.  This is useful
for basis set superposition error (BSSE) calculations.
----------------------------------------------------------
 
* * * If you gave $BASIS, continue entering cards -5U-
      until all the unique atoms have been specified.
      When you are done, enter a " $END " card.
* * * If you did not, enter cards -6U-, -7U-, -8U-.
 
----------------------------------------------------------
-6U-  GBASIS, NGAUSS, (SCALF(i),i=1,4)
 
GBASIS can have exactly the same meaning as the keyword in
$BASIS.  You may choose from STO, N21, N31, N311, ACCT,
PC4, ...  A few of these require NGAUSS below.
 
In addition, GBASIS can be S, P (or L), D, F, G, H, or I to
enter an explicit basis set.  L means both an S and P shell
with the same exponent.  See NGAUSS below.
 
In addition, GBASIS may be defined as MCP, to indicate that
the current atom is represented by a model core potential,
and valence basis set.  An internally stored basis and
potential will be applied (see REFS.DOC for the details).
The MCP basis supplies only the occupied atomic orbitals,
e.g. sp for a main group element, so please supplement with
any desired polarization.  In case the keyword MCP is
followed by the keyword READ, everything will be taken from
the input file, namely the basis functions are read using
the sequence -6U-, -7U-, and -8U-, from lines following the
"MCP READ" line.  In addition, "MCP READ" implies that the
parameters of the model core potentials, together with core
basis functions are in the input stream, in a $MCP input
group.  Other MCP bases are available in the $BASIS input,
but note that to locate the MCP, the atom name must be a
chemical symbol, that is "P" instead of "Phosphorus".
 
NGAUSS is the number of Gaussians (N) in the Pople style
basis, or user input general basis.  It has meaning only
for GBASIS=STO, N21, N31, or N311, or explicit GTO types
such as S,P,D,F...
 
Up to 4 scale factors may be entered.  If omitted, standard
values are used.  They are not documented as every GBASIS
treats these differently.  Read the source code if you need
to know more.  They are seldom given.
----------------------------------------------------------
 
* * * If GBASIS is not S,P,D,F,... either add more
      shells by repeating card -6U-, or go on to -8U-.
* * * If GBASIS=S,P,D,F,... enter NGAUSS cards -7U-.
 
----------------------------------------------------------
-7U- IG, ZETA, C1, C2
 
      IG = a counter, IG takes values 1, 2, ..., NGAUSS.
    ZETA = Gaussian exponent of the IG'th primitive.
      C1 = Contraction coefficient for S,P,D,F,G shells,
           and for the s function of L shells.
      C2 = Contraction coefficient for the p in L shells.
----------------------------------------------------------
 
* * * For more shells on this atom, go back to card -6U-.
* * * If there are no more shells, go on to card -8U-.
 
----------------------------------------------------------
-8U-    A blank card ends the basis set for this atom.
----------------------------------------------------------
 
Continue entering atoms with -5U- through -8U- until all
are given, then terminate the group with a " $END " card.
 
       --- this is the end of card sequence U ---
 
COORD=CART input:
 
----------------------------------------------------------
 
-5C- Atom input.
 
Cartesian coordinates for all atoms must be entered.  They
may be arbitrarily rotated or translated, but must possess
the actual point group symmetry.  GAMESS will reorient the
molecule into the 'master frame', and determine which
atoms are the unique ones.  Thus, the final order of the
atoms may be different from what you enter here.
 
      NAME, ZNUC, X, Y, Z
 
NAME  = 10 character atomic name, used only for printout.
        Thus you can enter H or Hydrogen, or whatever.
ZNUC  = nuclear charge.  It is the nuclear charge which
        actually defines the atom's identity.
X,Y,Z = Cartesian coordinates.
 
----------------------------------------------------------
 
Continue entering atoms with card -5C- until all are
given, and then terminate the group with a " $END " card.
 
       --- this is the end of card sequence C ---
 
COORD=ZMT input:       (GAUSSIAN style internals)
 
----------------------------------------------------------
 
-5G-      ATOM
 
Only the name of the first atom is required.
See -8G- for a description of this information.
----------------------------------------------------------
 
-6G-      ATOM  i1 BLENGTH
 
Only a name and a bond distance is required for atom 2.
See -8G- for a description of this information.
----------------------------------------------------------
 
-7G-      ATOM  i1 BLENGTH  i2 ALPHA
 
Only a name, distance, and angle are required for atom 3.
See -8G- for a description of this information.
----------------------------------------------------------
 
-8G-      ATOM  i1 BLENGTH  i2 ALPHA  i3 BETA i4
 
ATOM    is the chemical symbol of this atom.  It can be
        followed by numbers, if desired, for example Si3.
        The chemical symbol implies the nuclear charge.
i1      defines the connectivity of the following bond.
BLENGTH is the bond length "this atom-atom i1".
i2      defines the connectivity of the following angle.
ALPHA   is the angle "this atom-atom i1-atom i2".
i3      defines the connectivity of the following angle.
BETA    is either the dihedral angle "this atom-atom i1-
        atom i2-atom i3", or perhaps a second bond
        angle "this atom-atom i1-atom i3".
i4      defines the nature of BETA,
        If BETA is a dihedral angle, i4=0 (default).
        If BETA is a second bond angle, i4=+/-1.
        (sign specifies one of two possible directions).
----------------------------------------------------------
 
 o  Repeat -8G- for atoms 4, 5, ...
 o  The use of ghost atoms is possible, by using X or BQ
    for the chemical symbol.  Ghost atoms preclude the
    option of an automatic generation of $ZMAT.
 o  The connectivity i1, i2, i3 may be given as integers,
    1, 2, 3, 4, 5,...  or as strings which match one of
    the ATOMs.  In this case, numbers must be added to the
    ATOM strings to ensure uniqueness!
 o  In -6G- to -8G-, symbolic strings may be given in
    place of numeric values for BLENGTH, ALPHA, and BETA.
    The same string may be repeated, which is handy in
    enforcing symmetry.  If the string is preceded by a
    minus sign, the numeric value which will be used is
    the opposite, of course.  Any mixture of numeric data
    and symbols may be given.  If any strings were given
    in -6G- to -8G-, you must provide cards -9G- and
    -10G-, otherwise you may terminate the group now with
    a " $END " card.
 
----------------------------------------------------------
 
-9G-   A blank line terminates the Z-matrix section.
 
----------------------------------------------------------
 
-10G-   STRING VALUE
 
STRING is a symbolic string used in the Z-matrix.
VALUE  is the numeric value to substitute for that string.
 
----------------------------------------------------------
 
Continue entering -10G- until all STRINGs are defined.
Note that any blank card encountered while reading -10G-
will be ignored.  GAMESS regards all STRINGs as variables
(constraints are sometimes applied in $STATPT).  It is not
necessary to place constraints to preserve point group
symmetry, as GAMESS will never lower the symmetry from
that given at -2-.  When you have given all STRINGs a
VALUE, terminate the group with a " $END " card.
 
       --- this is the end of card sequence G ---
 
                      * * * *
 
    The documentation for sequence G above and sequence M
below presumes you are reasonably familiar with the input
to GAUSSIAN or MOPAC.  It is probably too terse to be
understood very well if you are unfamiliar with these.  A
good tutorial on both styles of Z-matrix input can be
found in Tim Clark's book "A Handbook of Computational
Chemistry", published by John Wiley & Sons, 1985.
 
    Both Z-matrix input styles must generate a molecule
which possesses the symmetry you requested at -2-.  If
not, your job will be terminated automatically.
 
COORD=ZMTMPC input:       (MOPAC style internals)
 
----------------------------------------------------------
 
-5M-     ATOM
 
Only the name of the first atom is required.
See -8M- for a description of this information.
----------------------------------------------------------
 
-6M-     ATOM BLENGTH
 
Only a name and a bond distance is required for atom 2.
See -8M- for a description of this information.
----------------------------------------------------------
 
-7M-     ATOM BLENGTH j1 ALPHA j2
 
Only a bond distance from atom 2, and an angle with respect
to atom 1 is required for atom 3.  If you prefer to hook
atom 3 to atom 1, you must give connectivity as in -8M-.
See -8M- for a description of this information.
----------------------------------------------------------
 
-8M-     ATOM BLENGTH j1 ALPHA j2 BETA j3 i1 i2 i3
 
ATOM, BLENGTH, ALPHA, BETA, i1, i2 and i3 are as described
at -8G-.  However, BLENGTH, ALPHA, and BETA must be given
as numerical values only.  In addition, BETA is always a
dihedral angle.   i1, i2, i3 must be integers only.
 
The j1, j2 and j3 integers, used in MOPAC to signal
optimization of parameters, must be supplied but are
ignored here.  You may give them as 0, for example.
----------------------------------------------------------
 
Continue entering atoms 3, 4, 5, ... with -8M- cards until
all are given, and then terminate the group by giving a
" $END " card.
 
       --- this is the end of card sequence M ---
 
 
 
If you have any doubt about what molecule and basis set
you are defining, or what order the atoms will be
generated in, simply execute an EXETYP=CHECK job to find
out!