论文部分内容阅读
Helix-Symmetrical polymer possesses not only translation symmetry but also rotationsymmetry.On the basis of this kind of symmetry,a new linear combination method named as LCAO/To-LCTO/HO-LCHO/PO has been established to derive the secular equation for this kind of poly-mers.In such a manner,the order of secular equations can be reduced from n×P to P(where n isthe number of atomic orbitals in each translational unit,and P is the same number but in eachhelical unit),thus cbtaining the maximum factorization of the secular equations and favoring thesymmetrical analysis of the results.The computational program corresponding to the EHMOscheme was edited for calculating the helix-symmetrical polymers.In principle,this treatment can be applied to the other quantum chemistry computation.Takepolyethylene and polyacetylene as examples,the energy bands with 2_1,3_1 and 4_1 helical comformationswere calculated by the computional program.The discussions on the influence of the variation ofcomformations to energy bands and the related physical and chemical properties were given.
Helix-Symmetrical polymer possesses not only translation symmetry but also rotationsymmetry. On the basis of this kind of symmetry, a new linear combination method named as LCAO / To-LCTO / HO-LCHO / PO has been established to derive the secular equation for this kind of poly-mers.In such a manner, the order of secular equations can be reduced from n × P to P (where n is the number of atomic orbitals in each translational unit, and P is the same number but in eachhelical unit) thus cbtaining the maximum factorization of the secular equations and favoring the asymmetrical analysis of the results. computational program corresponding to the EHMOscheme was edited for calculating the helix-symmetrical polymers.In principle, this treatment can be applied to the other quantum chemistry computation. and polyacetylene as examples, the energy bands with 2_1,3_1 and 4_1 helical comformationswere calculated by the computional program.The discussions on the influence of the variation ofcomformati ons to energy bands and the related physical and chemical properties were given.