An interaction potential at different orientation for the CH4 and CO2 complex was derived at theB3LYP level of theory and 6-31+G* basis sets. The potential energy surface was computed on somemolecular geometries. The complete basis set limit of the interaction energies were fitted to wellknownanalytical functions. To determine the second virial coefficients B, U(r) is used to obtain themodel’s ...

Calculations for optical excitations in confined systems require knowledge of the inverse screening dielectric function epsilon(-1)(r,r(')), which plays a crucial role in determining exciton binding energies. We present a new efficient real-space method of inverting and storing large ab initio dielectric matrices of confined systems, which relies on the separability of epsilon matrix in r and r...

Structures and electronic states of the HOO radical interacting with water molecules, expressed by HOO(H2O)n (n = 1 and 2), have been investigated by means of a direct ab initio molecular dynamics (MD) method. From the static ab initio calculation of HOO-H2O complex, two types of HOO radical were found: i.e., the HOO radical acts as a hydrogen donor or acceptor in the complex (n = 1). The bindi...

Ab initio calculations have been carried out on the potential energy curves of the Rydberg states of NeH up to 3d . Quantum defect functions have been calculated from the ab initio potentials and potential energy curves and vibrational levels for higher n (s ,p ,d) Rydberg states have been generated. The interaction of the 2p B P state with the 2s and 2p , A S and C S states and their predissoc...

We present two new methods for molecular dynamics simulations based on general HartreeFock (GHF) theory. The first method involves approximating ab initio STO-3G matrix elements with fitting functions to enable faster computation of the energy and forces for molecular dynamics simulations. The implementation of this method includes a frozen-core approximation. The second method involves develop...

: in this work, different levels of theory containing hf, b3lyp, and mp2 with different basis sets such as 6-31g, 6-31g*, 6-311g, 6-311+g, 6-31+g*, 6-31+g are used to predict relative acidity constants of some aniline derivatives. three different kinds of radii containing uahf, bondi, and pauling are used to study how cavity forms change acidity constants. in all cases, dpcm model is used to si...

in this study, b12n12 nano ring has been selected because it consist of four 6-side rings and polar bonds b-n which in comparison with non-polar bonds c-c, is more suitable for the study of the absorption of other compounds. so reactivity and stability of benzene alone and in the presence b12n12 nano ring field checked. to determine the non-bonded interaction energies between benzene and b12n12...

the intermolecular forces between water molecules are of great importance in many areas of chemistry including solvation, solution chemistry, and biochemistry. as a result of this (h2o)n systems have received a great significant of attention, both experimental and theoretical. all calculation of this study are carried out by gaussian 98 soft ware. geometry optimization for each cluster were be ...

to investigate non-bonded interaction of phenanthrene and bn nanostructure, geometric structure of phenanthrene and b12n12 nano-ring with b3lyp method and 6-31g* basis set are optimized by using ab initio gaussian quantum chemical package. the main purpose of this study was to evaluate changes of electronic properties of aromatic compound in presences nano ring field. therefore reactivity and s...