Elektrik multipol momentlerin teorisi ve bazı iki atomlu moleküllere uygulanması
Tez Türü: Doktora
Tezin Yürütüldüğü Kurum: Ondokuz Mayıs Üniversitesi, Lisansüstü Eğitim Enstitüsü, Fizik Anabilim Dalı, Türkiye
Tez Danışmanı: Emin Öztekin
Tezin Onay Tarihi: 2000
Tezin Dili: Türkçe
Özet:
One of the most important properties of molecules apart from the energy is the determination of their charge distributions. This is described in terms of electric multipole moments. Since experimental methods are limited to the dipole and quadrupole moments, it increases the interest of theoretical investigation on electric multipole moments. In this study, the average values of 2'' -pole molecular electric multipole moments using Slater type orbitals (STO's) with the help of the Hartree-Fock- Roothaan (HFR) method were described in terms of a) multicenter electric multipole moment integrals, b) linear combination coefficients of molecule orbitals. In order to evaluate multicenter electric multipole moment integrals, the analytical and series expressions were derived using translation formulas for electric multipole moment operator and STO's, respectively. The computer programs using Turbo Pascal 7.0 language were constructed for these expressions and the other analytical expression in literature. Both analytical expressions results for various values of integral parameters were in agreement with each other and it was seen that the new analytical expression was faster than the other in view of the computer process time. Moreover, it was seen that the computer results obtained from derived new analytical and series expressions were in agreement with each other for at least fife decimal digits for various values of integral parameters. With the help of the symmetry properties of A2 and AB type molecules, the necessary symmetry properties for linear combination coefficients of molecular orbitals were found out. After then, the orbital energies, total energies and linearcombination coefficients of molecules Li2, N2, F2, I AH, BH, HF and CO in ground state were calculated using computer programs constructed for HFR equations over STO's. It was observed that the necessary symmetry properties for linear combination coefficients of molecular orbitals and the total energies were in agreement with the results in literature. In calculation of electric multipole moments, it was accepted that diatomic molecules were placed on z-axes and then dipole, quadrupole, octupole and hexadecapole moments were calculated. Apart from the dipole and quadrupole moments of CO, the obtained electric multipole moment values were in agreement with the experimental and theoretical results in literature. Key Words: Electric multipole moment, Slater type orbital (STO), Hartree-Fock- Roothaan (HFR) equation, Overlap integrals.