5323

4993

كارشناسي ارشد

شيمي فيزيك

اصفهان: دانشگاه صنعتي اصفهان، دانشكده فيزيك

1388

شانزده،154ص.:مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

حسين فرخ پور

محمود تبريزچي

15/4/89

حسن حدادزاده،مجتبي اعلائي

فيزيك

ID4993

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Intermolecular Potential Energy Surface for CS2 Dimer and Calculation of Second virial coefficient Zeinab Mombeini z mombeinee@yahoo com Department of Chemistry Isfehan of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Hossein Farrokhpour farrokhphossein@gmail com Abstract Computational chemistry simulates chemical structures and reactions numerically based on the fundamental laws of physics using two different methods including electronic structure and molecular mechanics In this work a four dimension intermolecular potential energy surface for CS2 CS2 system is obtained by ab initio calculation of the potential energies for a range of configurations and intermolecular distances The calculations were performed using the supermolecular approach on the MP2 level of theory with the augmented correlation consistent aug cc pVXZ X D T basis sets using rigid rotor approximation The number of configuration points were selected for calculations is 1387 The calculated energy points were corrected for the basis set superposition error using the full counterpoise correction method suggested by Boys and Bernardi A two point extrapolation method was used to extrapolate the calculated correlation energy points to the complete basis set limit and the Hartree Fock energy part has not been extrapolated but taken from the aug cc pVTZ calculations The extrapolated intermolecular energy points were fitted to the exp 6 potential function to represent the potential energy surface analytically The results show that the most stable configuration of CS2 CS2 system is cross configuration 1 90 2 90 and 90 at R 6 23 Bohr with a well depth of 3 98 0 018 kcal mol and the most unstable configuration is linear 1 0 2 0 and 0 at R 12 548 Bohr with a well depth of 1 48 0 018 kcal mol The second virial coefficients have been calculated using the scaled potential energy surface over a range of temperature 280 470 K and compared with the experimental values to test the quality of the presented potential energy surface Also we used global fitting to have a simple analytical spherical one center intermolecular potential using exp 6 and lennard jones potential separately The parameters of the potential were obtained by radial fitting of the intermolecular interaction potential of all configurations with exp 6 and lennard jones simultaneously The obtained potential parameters for the exp 6 and lennard jones potentials are 00265 0000943 hartree Rm 6 45 0258 Bohr 10 0 231 and 00304028 0000972 hartree 5 478 0122 respectively Keywords Surface potential energy of CS2 CS2 system Moller Peleset aug cc pVXZ X D T exp 6 potential function Lenard Jones potential function second virial coefficient

حسين فرخ پور

محمود تبريزچي

حسن حدادزاده،مجتبي اعلائي