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Information on MM2/MM3

[ MM2 ] [ MM3 ] [ MEDIT ] [ MINP ] [ CRSTL ]

MM2


MM2 force field for hydrocarbons was described in ref. [1]. Extensions to functionalized molecules have been described in subsequent papers and summarized in ref. [2]. The original program (MM2(77)) is available from the Quantum Chemistry Program Exchange (QCPE), University of Indiana, Bloomington, IN 47405, Program 395. The latest version of MM2, referred to as MM2(87) is available to academic users from QCPE and to all users from Tripos, Inc., 1699 South Hanley Road, St Louis, MO 63144.


MM2 Atom Type List

View MM2 known bugs

Report MM2 Bug


[1] Allinger, N. L., J. Amer. Chem. Soc., 99, 8127 (1977).
[2] Burkert, U. and N. L. Allinger, Molecular Mechanics, American Chemical Society: Washington, DC, 1982.

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MM3


The MM3 program is available to academic users from the Quantum Chemistry Program Exchange (QCPE), University of Indiana, Bloomington, IN 47405. The package is also available to all users from Tripos, Inc., 1699 South Hanley Road, St Louis, MO 63144.

The latest version of MM3 is MM3(2000). The program is available to academic users from Allinger's lab, and to all users from Tripos, Inc. (see contact information below).



MM3 Performance on Selected Machines

MM3 Atom Type List

View MM3 known bugs

Report MM3 Bug


[1] Allinger, N. L., Y. H. Yuh, and J. H. Lii, J. Amer. Chem. Soc., 111, 8551 (1989).
[2] Lii, J. H. and N. L. Allinger, J. Amer. Chem. Soc., 111, 8566 (1989).
[3] Lii, J. H. and N. L. Allinger, J. Amer. Chem. Soc., 111, 8576 (1989).

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MEDIT


MEDIT is a graphical interface to MM2 and MM3. It allows the user to draw a molecule on the computer screen, edit it, run MM2/MM3 to minimize its energy, and display the results. Although it lacks the comprehensive utilities of large, expensive systems, it has several advantages too. It is easy to use, fast, takes little disk space.

What is needed to run MEDIT? A Tektronix 4014 terminal or its emulators, such as Tek terminal emulator in UNIX X-Window system (use "xterm -t&" command), MS_Kermit(for PC) and Versterm (for Mac), and pointing device. The MEDIT program is included in MM3 package which is available from QCPE. Click here for more information on MEDIT. Click here to reprot MEDIT bug.

MEDIT program can read MM2/MM3, SYBYL(MOL), GAUSSIAN output format file, and etc.

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MINP


The MINP is a MM2/MM3 input assist program. The program is a modification of STR program (QCPE 488), by Ronald M. Jarret and Martin Saunders). Starting from any atom and any numbering system, using types and directions of successive bonds to other atoms, then program generates Cartesian coordinates for all atoms in the molecule. The output file is directly suitable for either Allinger's MM2(77), MM2(85), MM2(87) or MM3 molecular mechanics programs with default options (see MM2 or MM3 user manual). The MINP program is included in the MM3 package, and is also available from QCPE, program 543 or QCMP032. The MINP program is for standard text terminals.

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CRSTL


The CRSTL program is used to optimize the lattice parameters of the crystal, such as a, b, c, alpha, beta, gamma as well as Eulerian angles theta_x, theta_y and theta_z which define the orientation of molecule itself. The program can handle more complicated crystal system which has more than one molecule (with same conformation) in the unit cell.

For the case of one molecule in the unit cell (space group p1, for example), the total crystal geometrical parameters are nine, as we mentioned earlier. While for the case of two or more molecules in the unit cell (e.g. space group p1 bar), six more parameters (tx, ty, tz, rx, ry, rz) for each additional molecule are needed to define the rest of molecules in the unit cell. There are total of 27 parameters to define the whole crystal system.

In this program, the molecule itself is treated as rigid molecule during the lattice parameters optimization. The CRSTL program use SIMPLEX optimization method. The CRSTL program is included in the MM3 package and available from QCPE. Click here for more information.


[1] Lii, J. H. and N. L. Allinger, J. Amer. Chem. Soc., 111, 8576 (1989).

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by Jenn-Huei Lii ( robert@europa.chem.uga.edu)

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