Title of program: AMYR Method of solution The stable conformation(s) of the molecular association is (are) Catalogue number.' ACEO found by minimization of the energy of interaction between the two molecules. The energy is evaluated by means of a l/R Program obtainablefrom: CPC Program Library, Queen's Urn-expansion (with R -', R~, R 6 and R -12 terms), With coeffiversity of Belfast, N. Ireland (see application form in this issue) cients obtained by fitting of accurate SCF results [I]. The energy minimization is carried out by a steepest-descent method. Computer for which the program is designed and others on which it is operable: Amdahl 580/5860 and IBM-type computers; also Restrictions on the complexity ofthe problem FPS-190L Calculations should be restricted to molecules consisting of atoms belonging to the thirty classes for which expansion Computer: Amdahl 580/5860; Installation: University of Al-coefficients are available. berta Computing Services Typical running time Operating system: MTS 310 s for the test run (with three cases). Programming language used: Fortran IV Unusualfeatures of the program This program has been prepared from a version, in operation at High speed storage required: 104 Kwords the University of Alberta, which runs on a FPS-190L array processor and produces the plots of the conformation of the No. of bits in a word: 32 molecular complex on a Tektronix T-4015-I terminal adapted with a hard copier. The original program may be easily regener-Peripherals used: disks, printer ated from this published version. No. of lines in combined program and test deck: 2198 Reference [I] S. Fraga, J. Comput. Chetn. 3 (1982) 329.