MacroModel Reference Manual - ISP

MacroModel Reference ManualAppendix FAppendix F: Format of .grd FilesFiles with a .grd suffix are produced by the DRIV command. These files are used by Maestroto create contour plot displays.Although right now Maestro and DRIV support two-dimensional data, the file format isdesigned to accommodate three dimensional data sets. The format is as follows. Fortran formatdescriptors are given for each part of the file. This file format is based on the Gaussian-90 electron-densityfile format.Line 1: Format (A80). In general, this can contain any string, and can be used as a title line;however, if this line contains the string BMIN in the columns 1-4 followed by a list of atomnumbers in (4I5) format, Maestro will attempt to display the molecule in file filenameout.mae,where filename is the prefix of the .grd file, and will use the atom numbers to associatethe contour display with the torsion.Line 2: Format (A80). As for line 1. The atom numbers define the second dihedral which wasdriven during the calculation.Line 3: Format (I5,3F12.6). Natoms, X-Origin, Y-Origin, Z-Origin. Natoms is the number ofatoms in the molecule. The X-Origin and Y-Origin variables define the axis values of the“origin” (bottom left) of the contour plot. These will be taken from the starting angles in theDRIV command; for example, they might both be –180.0.Lines 4-6: Format (I5,3F12.6). Ninc, Xinc, Yinc, Zinc. Each of the three lines is for one drivenangle. Ninc is the number of increments of the angle and Xinc, Yinc, and Zinc are the componentsof an increment along the axes of the first, second, and third driven angle. Since forDRIV-generated data the angles are driven separately and independently, and since we nowsupport only the two-dimensional case, lines 4-6 should have the following form:NN NN.NNNNNNN 0.000000 0.000000NN 0.000000 NN.NNNNNN 0.0000000 0.000000 0.000000 0.000000NN is the number of increments of the angle and NN.NNNNNN is the size of an increment.There next follow Natoms lines, starting with line 7. Each line has format (I5, 4F12.6), and thevariables are atomic number, charge, and X, Y, and Z coordinates. These lines are actuallyignored by MacroModel, but must be present.MacroModel 9.7 Reference Manual 225