9 research outputs found
Lower Rydberg series of methane : A combined coupled cluster linear response and molecular quantum defect orbital calculation
Vertical excitation energies as well as related absolute photoabsorption oscillator strength data are very scarce in the literature for methane. In this study, we have characterized the three existing series of low-lying Rydberg states of CH4 by computing coupled cluster linear response (CCLR) vertical excitation energies together with oscillator strengths in the molecular-adapted quantum defect orbital formalism from a distorted Cs geometry selected on the basis of outer valence green function calculations. The present work provides a wide range of data of excitation energies and absolute oscillator strengths which correspond to the Rydberg series converging to the three lower ionization potential values of the distorted methane molecule, in energy regions for which experimentally measured data appear to be [email protected] [email protected] [email protected]
Erratum: âDensity-functional and electron correlated study of five linear birefringencesâKerr, CottonâMouton, Buckingham, Jones and magnetoelectricâin gaseous benzeneâ J. Chem. Phys. 121, 8814 2004; âDensity-functional study of electric and magnetic properties of hexafluorobenzene in the vapor phaseâ J. Chem. Phys. 122, 234314 2005; and âA computational study of some electric and magnetic properties of gaseous BF3 and BCl3â J. Chem. Phys. 123, 114307 2005
Erratum: âDensity-functional and electron correlated study of five linear
birefringencesâKerr, CottonâMouton, Buckingham, Jones and
magnetoelectricâin gaseous benzeneâ â J. Chem. Phys. 121, 8814 â2004âŠâĄ;
âDensity-functional study of electric and magnetic properties of
hexafluorobenzene in the vapor phaseâ â J. Chem. Phys. 122, 234314
â2005âŠâĄ; and âA computational study of some electric and magnetic
properties of gaseous BF3 and BCl3â â J. Chem. Phys. 123, 114307
â2005âŠ
A computational study of some electric and magnetic properties of gaseous BF3 and BCl3
We present the results of an extended computational study of the electric and magnetic properties
connected to Cotton-Mouton birefringences, on the trifluoro- and trichloroborides in the gas phase.
The electric dipole polarizabilities, magnetizabilities, quadrupole moments, and higher-order
hypersusceptibilitiesâexpressed as quadratic and cubic frequency-dependent response functionsâ
are computed within Hartree-Fock, density-functional, and coupled-cluster response theories
employing singly and doubly augmented correlation-consistent basis sets and London orbitals in the
magnetic property calculations. The results, which illustrate the capability of time-dependent
density-functional theory for electron-rich systems, are compared with available experimental data.
Revised values of both experimentally derived quadrupole moment of BF3, 2.72±0.15 a.u., and
magnetizability anisotropy of BCl3, â0.45±0.09 a.u., both obtained in birefringence experiments
that neglect the effects of higher-order hypersusceptibilities, are presented. In the theoretical limit
the traceless quadrupole moments of BF3 and BCl3 are determined to be 3.00±0.01 and
0.71±0.01 a.u., respectively
Cholesky decomposition techniques in electronic structure theory
We review recently developed methods to efficiently utilize the Cholesky decomposition technique in electronic structure calculations. The review starts with a brief introduction to the basics of the Cholesky decomposition technique. Subsequently, examples of applications of the technique to ab inito procedures are presented. The technique is demonstrated to be a special type of a resolution-of-identity or density-fitting scheme. This is followed by explicit examples of the Cholesky techniques used in orbital localization, computation of the exchange contributionto the Fock matrix, in MP2, gradient calculations, and so-called method specific Cholesky decomposition. Subsequently, examples of calibration of the method with respect to computed total energies, excitation energies, and auxiliary basis set pruning are presented. In particular, it is demonstrated that the Cholesky method is an unbiased method to derive auxiliary basis sets. Furthermore, details of the implementational considerations are put forward and examples from a parallel Cholesky decomposition scheme is presented. Finally, an outlook and perspectives are presented, followed by a summary and conclusions section. We are of the opinion that the Cholesky decomposition method is a technique that has been overlooked for too long. We have just recently started to understand how to efficiently incorporate the method in existing ab initio programs. The full potential of the Cholesky technique has not yet been fully explored
Cohort profile. the ESC-EORP chronic ischemic cardiovascular disease long-term (CICD LT) registry
The European Society of cardiology (ESC) EURObservational Research Programme (EORP) Chronic Ischemic Cardiovascular Disease registry Long Term (CICD) aims to study the clinical profile, treatment modalities and outcomes of patients diagnosed with CICD in a contemporary environment in order to assess whether these patients at high cardiovascular risk are treated according to ESC guidelines on prevention or on stable coronary disease and to determine mid and long term outcomes and their determinants in this population