A general theory for response properties is presented which is applicable to perturbations affecting the molecular basis set, notably nuclear derivatives. A perturbation-independent Fock space is introduced, and the necessary reorthonormalization of a truncated basis set after a perturbation is explicitly incorporated in the Hamiltonian. Explicit formulas for MCSCF firstand second-order propert...

Synopsis We present a combined experimental and theoretical study focused on the ionic states of the N2O4 molecule. Experimental results regarding photoionization induced by the synchrotron radiation SOLEIL in the 13.5-15.5 eV energy range were obtained using the electron-ion velocity vector correlation method. The potential energy curves for the dissociation of the N-N bond were computed withi...

one of the most important advantages of particle simulation as compared to fluid simulation is the capacity for working with and tracing particles. in particle simulations, the test particle method is usually used to get some idea of the behavior of plasma or other substances. in this method, first, a small number of particles are injected into the frame of static electromagnetic fields. then, ...

We present the hamiltonian structures for a wide class of coupled Korteweg-de Vries systems, including the Gear and Grimshaw system that models the strong interaction of internal waves in a stratified liquid and the system of Lou, Tong, Hu and Tang that describes a two layer fluid model. Among the hamiltonian structures of these systems we found new Poisson brackets which define consistent alge...

The rates of the electric quadrupole E2 and magnetic dipole M1 forbidden transitions in the ground configuration and some excited configurations of the Ti XIX ion have been calculated. The multiconfiguration Hartree Fock (MCHF) method has been used. The relativistic corrections are included in the Breit Pauli approximation. A detailed comparison of the present theoretical results with previous ...

A number of models are being developed for the traffic, service and queuing in the emerging telecommunication networks. The task is rather difficult because the traffic is bursty and correlated. These models include the compound Poisson process (CPP), the Markov modulated Poisson process (MMPP) and self-similar traffic models such as the Fractional Brownian Motion (FBM). The CPP and the ∑K k=1 ...

A comprehensive investigation of the pp*, np* and ps* excited states of xanthine has been performed with the CASSCF, CASPT2, CC2 and ADC(2) methods. The 7H-diketo and 9H-diketo tautomers of xanthine, which are the lowest-energy tautomers in the ground state, have been studied. Out-of-plane deformation of the purine system in the lowest pp* state as well as dissociation of the NH bonds in the lo...

Low-energy electron impact excitations of S2 molecules are studied using the fixedbond R-matrix method based on state-averaged complete active space SCF orbitals. Integral cross sections are calculated for elastic electron collision as well as impact excitation of the 7 lowest excited electronic states. Also, differential cross sections are obtained for elastic collision and excitation of the a...

Different types of Gaussian basis sets for accurate LCAO calculations are discussed. For calculations designed to recover a substantial portion of the correlation energy, we suggest the use of basis sets comprising natural orbitals from correlated calculations on the atoms. These basis sets have proven to be very efficient in accounting for large fractions of the molecular correlation energy. F...