The Application of ab-initio quantum theory is restricted for bigger systems due to huge computation costs. In this work a new approach is described which allows us to apply an ab-initio quantum method for bigger systems. It is shown that the dynamical electron correlation may be achieved by relaxing Pauli’s exclusion principle partially. Thus, a restricted Hartree-Fock electron conﬁguration may be considered as a perturbed system of the exact conﬁguration. Using this physical concept, the matrix elements of the relaxation operators are constructed. Projecting this relaxation operator on to Hartree-Fock wave function gives dynamical electron correlation energy directly. This method is simpleandimplementedsuccessfullyforazuleneanditschloridederivativetopredicttheirabsorption spectra.
Department of Applied Sciences, Maulana Abul Kalam Azad University of Technology, West Bengal, Simhat, Haringhata, Nadia, Pin Code – 741249, India.
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