APPLICATION OF PERTURBATION THEORY AND VARIATION METHOD TO CALCULATE LOWER ENERGY LEVELS OF HELIUM ATOM

Abstract

This thesis presented how one found the energy and the wave function formalism of helium atom, for the lower energy level of general space dependent potential. Using perturbation and Varitional approximation method.The solution of the time independent Schrodinger equation was a slowly varied functions, that we performed in the calculation employed by Varitional method with one parameter in the ground and exited state of two particles with trial wave function. We got better result in ground state Varitional calculation from perturbation one. Whereas, the result of the varitional calculation in the excited state not more accurate because excited state of varitional treatment solved with advanced software and also we could not performed the calculation with one varitional parameters.In the case of perturbation treatment initially we performed our calculation without considered effective nuclear charge, the result of the calculated value was failed. Then after we considered shielding effect of the electron in the perturbation term, our calculated results were quite accurate for both ground and excited state with that of the experimental values.as a result, we conclude that, one could solved two electrons system by employed perturbation treatment, and applied appropriate effective nuclear charge in the wave function formalism that, we have used in first order energy correction formalism.