Capabilities of ATOMS
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ATOMS is a program to display atomic structures of all types, including molecules, polymers and crystals, and combinations of any of these.

If symmetry is used, the coordinates of only one atom of each equivalent set need to be entered. The symmetry elements for all 230 space groups and 32 crystallographic point groups are on file and can be called up by number or with their standard symbols. Non-crystallographic symmetry - such as pentagonal or icosahedral - can also be used. An auxiliary program SYMGRP is provided to derive complete symmetry matrices for any point group. ATOMS also supports Shubnikov symmetry for illustration of magnetic or other vectorial aspects of structures.

The boundaries for drawings of crystals and polymers can be specified in several ways. First, the contents of any given number of unit cells can be shown by setting limits to translational repetition. Second, any crystal faces, at any distance from the origin, may form the boundaries. Third, there is an option to show a slice of the structure parallel to a specified face with thickness equal to the d-spacing. Different boundary levels may be specified for different atoms if necessary. Fourth, a sphere about any atom or arbitrary point may be shown. Fifth, all molecules or other bonded units may be identified and shown in their entirety.

Molecules, polymers or other bonded groups may be isolated (independently of the fifth boundary option above). The generated atoms may be converted to input atoms, so that individual atoms may be deleted, removed or otherwise modified without affecting symmetry- or lattice-equivalent atoms.

Individual structure fragments may be combined to model twinning, epitaxy and crystalline defects.

There are several ways of displaying atoms and bonds in the Standard Model mode: (1) spherical atoms and stick or line bonds; (2) line bonds only; (3) interpenetrating spherical atoms; (4) coordination polyhedra. Any of these types of representation may be intermixed in a single drawing. In addition, there is a thermal ellipsoid mode which draws atoms and bonds in the manner of ORTEP (by Carroll K. Johnson). The same representations are available in both 2D (two-dimensional) and 3D (three-dimensional - OpenGL) Drawing modes.

Shading, according to angle of illumination, can be automatically applied to atoms, bonds and polyhedra in the 2D Drawing modes. The 3D Drawing modes, which use OpenGL, provide additional options for lighting and material properties. The 3D modes can display thermal ellipsoids in a variety of ways.

The Cavities Model mode shows a surface enclosing the possible center locations of a given-size spherical particle within the unit cell.

The drawing may be shown in strict projection, or in perspective at any given perspective distance. Exact scales may be specified in terms of inches or centimeters per Angstrom for the hard-copy output.

Separate stereopair images may be drawn and stereo output through quad-buffered OpenGL (or Direct3D on Windows) is available for appropriate hardware (suitable graphics cards, monitors, projectors and/or eyewear).

Atom labels and bond distances may be automatically added, drawn in proper location for stereopair views.

Hard copy can be made with dot-matrix printers, laser printers, inkjet printers or pen plotters. Also, you can write raster or bit-image files in several formats as well as vector files or metafiles, for use in other software. Files can also be written in 3D formats (3DMF, VRML).