AIMPAC Utilities						    gridv(3)

NAME
     gridv - calculates grid of values of rho or del2rho (in atomic 
             units) in a user specified plane of a molecule.
             It differs from grid only in that it is vectorized and 
             is thus much faster and is capable of doing finer
             grids in reasonable time - it is dimensioned to do
             a 400x400 grid currently. 

SYNOPSIS
     gridv infile wfnfile 

DESCRIPTION

        The gridv program reads the input data from the inffile 
        and the wavefuction from the wfnfile and calculates
        a square grid of values of the requested property.

ARGUMENTS

     infile (for example 'hcoh.inf')
        The input file describes the type and characteristics of the 
        desired calculation.

     wfnfile (for example 'hcoh.wfn')
        The wavefunciton file contains the basis set and optimized 
        coefficients from a SCF calculation describing the charge 
        distribution of that molecule.

FORMAT

        The input to GRIDV is free format with the first seven 
        characters of each card being ignored by the routine and used by 
        the user as labels for ease of use.  An example of the input is 
        given here. If the magnitude of the current density is being 
        calculated then there is a sixth and seventh card in which the 
        first seven characters are NOT ignored - i.e. put in only the 
        relevant numbers.

        TITLE:  Formaldehyde HF/3-21G//HF/3-21G rho 
        INCRM:  10.0 0.100
        CENTR:  0.0 0.0 0.0
        PLANE:  0 1 2 3 4
        NFUNC:  1

        The cards are used as follows:

        TITLE:  Formaldehyde HF/3-21G//HF/3-21G rho 
        The first card is a 60 character title card.

        INCRM:  10.0 0.100
        The second card defines the grid size and density.  The first 
        real number (N1) is the length of either axis of the grid in 
        atomic units (all values are in atomic units).  The second real 
        number (N2) is the distance between each grid point along the 
        axis.  This defines the density of the grid as there will be 
        N1/N2 points along each axis and hence (N1/N2)**2 grid points in 
        total.

        CENTR:  0.0 0.0 0.0
        The third card defines the center of the plot in the molecular 
        frame of reference.  The grid will be evenly placed about this 
        point.

        PLANE:  0 1 2 3 4
        The fourth card allows the user to define the plane of interest 
        for this calculation rotating it to the XY plane of the plotter. 
        The user has a choice of two methods for description of the 
        plane, inertial axis or Euler angles.  The first integer read 
        determines which method is used.  If the integer value is zero 
        inertial axis is to be used.  The integers following are the 
        atom numbers of those atoms within the plane.  Any number of 
        nuclei (up to 30) may be used to define the plane (three atoms 
        define a plane, but more may be entered).  In this case, the 
        user has requested that nuclei 1, 2, 3, and 4 be placed in the 
        plane.  If the atoms do not define a plane, the routine will 
        make a best fit to the plane and the results will most likely 
        not be desirable.  If the integer value is 1 then Euler angles 
        will be used.  The first real number is the rotation, in 
        degrees, about the molecular Z axis.  (Positive rotations 
        correspond to clockwise rotations when viewing down that axis 
        toward the origin from the positive axis)  The second real 
        number is the rotation about the molecular X axis.  The third is 
        the rotation about the Z axis of the plotter's frame.  For 
        example if the formaldehyde molecule were in the YZ plane in the 
        wavefunction file the following card would place the molecule in 
        the plotter's XY plane.
 
        PLANE:  1 90.0 90.0 0.0
        This corresponds to rotation about the Z axis, placing the 
        molecule in the XZ plane.  The second rotation about the X axis 
        places the molecule in the XY plane.  And the user has decided 
        not to reorient the molecule now that it is in the XY plane, 
        hence the third angle is 0.0.

        NFUNC:  1
        The fifth card chooses the function to be calculated at each 
        point in the grid.  An integer value of 1 chooses rho while a 
        value of 2 chooses del-squared rho.

OUTPUT

        GRIDV generates a file containing the requested grid of data. 
        This file will have the file extension '.grd'.  The grid may be 
        processed by running it through either contor or relief.

EXAMPLES

     gridv hcoh hcoh
        This requests a calculation of the grid described in hcoh.inf 
        using the wavefuction in hcoh.wfn.


INSTALLATION

        Compile with full vectorization optimization. Make sure you 
        are using the appropriate Matrix multiplication routines in the
        GAUS subroutine.

SEE ALSO
     contor(3), relief(3)

Release	1.0			  AIMPAC			    gridv(3)