New ab initio potential energy surfaces for the (2)Pi ground electronic state of the Ar-SH complex are presented, calculated at the RCCSD(T)/aug-cc-pV5Z level. Weakly bound rotation-vibration levels are calculated using coupled-channel methods that properly account for the coupling between the two electronic states. The resulting wave functions are analyzed and a new adiabatic approximation inc...

The previous paper [A. A. Veldhorst et al., J. Chem. Phys. 141, 054904 (2014)] demonstrated that the isomorph theory explains the scaling properties of a liquid of flexible chains consisting of ten Lennard-Jones particles connected by rigid bonds. We here investigate the same model with harmonic bonds. The introduction of harmonic bonds almost completely destroys the correlations in the equilib...

A variational optimization of the second-order density matrix under the P-, Q-, and G-conditions was carried out for a set of diatomic 14-electron molecules, including N(2), O(2) (2+), NO(+), CO, and CN(-). The dissociation of these molecules is studied by analyzing several chemical properties (dipole moments, population analysis, and bond indices) up to the dissociation limit (10 and 20 A). Se...

in this research at the first metoprolol drug and its fullerene derivative were optimized. natural bond orbital (nbo), nuclear indepndent chemical shift (nics) and finally ir calculations, for these compounds were carried out at the b3lyp/6-31g* quantum chemistry level. different parameters such as energy levels, the amount of chemical shift in different atoms, the amount of homo/lumo, chemical...

This paper offers some qualitative understanding of the chemical potential, a topic that students invariably find difficult. Three ‘‘meanings’’ for the chemical potential are stated and then supported by analytical development. Two substantial applications—depression of the melting point and batteries—illustrate the chemical potential in action. The origin of the term ‘‘chemical potential’’ has...

We demonstrate that the recently developed extended multi-state complete active space second-order perturbation theory (XMS-CASPT2) [Shiozaki et al., J. Chem. Phys., 2011, 135, 081106] provides qualitatively correct potential energy surfaces for low-lying excited singlet states of pyrazine, while the potential energy surfaces of the standard MS-CASPT2 methods are ill-behaved near the crossing p...

High level ab initio methods have been used to calculate values of the quadrupole moment of the ground X (1)Sigmag+ state of N2 on a dense radial mesh spanning the interval of 0.8-12.1 a.u. Detailed convergence tests indicate that the resulting equilibrium values of the quadrupole moment Theta(e)=-1.1273 a.u. and its first radial derivative dTheta(R)/dR/e=0.9604 a.u. have absolute uncertainties...