Using the line group symmetry within the modified group projector technique, POLSym® is designed to be used in polymer and nanotube research by differernt profiles of scientists, not necessarily acquainted with the group theory. The program can be used to predict the IC and Raman spectra, selection rules, second rank physical tensors, phase transitions. Research of the lattice dynamics of the modelled DNA molecule has been performed. At the moment, the nonexpert level completely covers the problems of the lattice dynamics (the vibrational zones of DNA are obtained in an hour, while the same task for polyacetylene is performed within 5 sec on the standard Pentium PC). It is expected that during 1999 the electronic states will be incorporated.
To enable the nonexpert level, the control over the program executing is performed through the system of menus. The main menu and the lattice dynamics menu are described in more details. For the experts, there are options for obtaining complete group theoretical data. These can be used by the program (or independently) in the problems still not covered within the nonexpert level.
| M A I N (experts
- nonexperts)
1 = Line group representations 2 = Operations with the representations 3 = Invariant polynomials 4 = Clebsch-Gordan coefficients 5 = Lattice dynamics 6 = View file 7 = EXIT |
Item 1 offers the choice of some representations of the line group: irreducible, polar, axial... Some of the standard operations with the representations (direct and (anti)symmetrical products, sum, decomposition...) are available- item 2. The invariant polinomials of the required degree found within the item 3, give the corresponding polinomial approximation of polymer potentials. The selection rules for processes in the polymer can be easily calculated within the item 4. |
| LATTICE DYNAMICS (experts
- nonexperts)
1 = Reduction of the dynamical representation 2 = Polymer configuration 3 = Interaction between the atoms in polymer 4 = Dynamical matrix 5 = Normal modes 6 = Vibrational zones 7 = Editing, graphics, TeX output 8 = EXIT |
The polymer is specified within the items 2 (configuration) and 3 (interaction, which can be given by the vibrational constants, or in the form of the various functions). By the options 1 and 4 the advanced applications are enabled. Item 5 gives the spatial geometry and the frequency of the normal vibrational mode corresponding to the previously prompted irreducible representation; together with the numerical output, the graphical animation of the obtained data is also produced. The complete vibrational zones, given as the graph w(k) (frequency as the function of the k vector from the Brillouine zone). For various numerical experiments, the fine tuning of the ionic configuration and the interactions is enabled by the item 7, together with graphical and tabular output of the results. |