Relativistic Dirac-Coulomb (DC) Hartree-Fock calculations are employed to obtain the analytic electric field gradient (EFG) on the antimony nucleus in the SbN, SbP, SbF, and SbCl molecules. The electronic correlation contribution to the EFGs is included with the DC-CCSD(T) and DC-CCSD-T approaches, also in the four-component framework, using a finite-difference method. The total EFG results, al...

Geometric and spectroscopic parameters are determined using explicitly correlated coupled cluster ab initio calculations (CCSD(T)-F12) for five monosubstituted isotopologues of acetone containing 1...

A time-dependent equation of motion coupled cluster singles and doubles (TD-EOM-CCSD) method is implemented, which uses a reduced basis calculated with the asymmetric band Lanczos algorithm. The approach used to study weak-field processes in small molecules induced by ultrashort valence pump core probe pulses. We assess reliability procedure comparing TD-EOM-CCSD absorption spectra obtained fro...

Coupled cluster theory is an attractive tool to solve the quantum many-body problem because its singles and doubles (CCSD) approximation computationally affordable yields about 90% of correlation energy. Capturing remaining 10%, e.g., via including triples, numerically expensive. Here, we assume that short-range three-body correlations dominate and---following Lepage (arXiv:nucl-th/9706029)---t...

A hierarchical family of five three-dimensional potential energy surfaces has been developed for the benchmark He-CO system. Four surfaces were obtained at the coupled cluster singles and doubles level of theory with a perturbational estimate of triple excitations, CCSD(T), and range in quality from the doubly augmented double-zeta basis set to the complete basis set (CBS) limit. The fifth corr...

The anti-cancer Nano drugs Cisplatin, Carboplatin, Nedaplatin, Oxaliplatin, Heptaplatin and Lobaplatin were characterized by 1HNMR, 13CNMR, 31PNMR, Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR), FT-Raman, HR Mass and UV-Vis spectroscopies and also by Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Differential Thermal Analysis-Thermal Gravim Anal...

The calculation of X-ray emission spectroscopy with equation of motion coupled cluster theory (EOM-CCSD), time-dependent density functional theory (TDDFT), and resolution of the identity single excitation configuration interaction with second-order perturbation theory (RI-CIS(D)) is studied. These methods can be applied to calculate X-ray emission transitions by using a reference determinant wi...

To obtain a state-of-the-art benchmark potential energy surface (PES) for the archetypal oxidative addition of the methane C-H bond to the palladium atom, we have explored this PES using a hierarchical series of ab initio methods (Hartree-Fock, second-order Møller-Plesset perturbation theory, fourth-order Møller-Plesset perturbation theory with single, double and quadruple excitations, coupled ...