Extension of the HF program to partially filled f-subshells

A new version of a Hartree-Fock program is presented that includes extensions for partially filled f-subshells. The program allows the calculation of term dependent Hartree-Fock orbitals and energies in LS coupling for configurations with no more than two open subshells, including f-subshells

Isotope shift in the Sulfur electron affinity: observation and theory

The electron affinities eA(S) are measured for the two isotopes 32S and 34S (16752.9753(41) and 16752.9776(85) cm-1, respectively). The isotope shift in the electron affinity is found to be positive, eA(34S)-eA(32S) = +0.0023(70) cm-1, but the uncertainty allows for the possibility that it may be either "normal" (eA(34S) > eA(32S)) or "anomalous" (eA(34S) < eA(32S)). The isotope shift is estimated theoretically using elaborate correlation models, monitoring the electron affinity and the mass polarization term expectation value. The theoretical analysis predicts a very large specific mass shift that counterbalances the normal mass shift and produces an anomalous isotope shift, eA(34S)-eA(32S) = - 0.0053(24) cm-1. The observed and theoretical residual isotope shifts agree with each other within the estimated uncertainties.Comment: 15 pages, 4 figure

A comparative laboratory trial evaluating the immediate efficacy of fluralaner, afoxolaner, sarolaner and imidacloprid + permethrin against adult Rhipicephalus sanguineus (sensu lato) ticks attached to dogs

Variational methods are used for targeting specific correlation effects by tailoring the configuration space. Independent sets of correlation orbitals, embedded in partitioned correlation functions (PCFs), are produced from multiconfiguration Hartree-Fock (MCHF) and DiracHartree-Fock (MCDHF) calculations. These non-orthogonal functions span configuration state function (CSF) spaces that are coupled to each other by solving the associated generalized eigenvalue problem. The Hamiltonian and overlap matrix elements are evaluated using the biorthonormal orbital transformations and efficient counter-transformations of the configuration interaction eigenvectors [1]. This method was successfully applied for describing the total energy of the ground state of beryllium [2]. Using this approach, we demonstrated the fast energy convergence in comparison with the conventional SD-MCHF method optimizing a single set of orthonormal one-electron orbitals for the complete configuration space. In the present work, we investigate the Partitioned Correlation Function Interaction (PCFI) approach for the two lowest states of neutral lithium, i.e. 1s 2 2s 2 S and 1s 2 2p 2 P o . For both states, we evaluate the total energy, as well as the expectation values of the specific mass shift operator, the hyperfine structure parameters and the transition probabilities using different models for tailoring the configuration space. We quantify the “constraint effect” due to the use of fixed PCF eigenvector compositions and illustrate the possibility of a progressive deconstraint, up to the non-orthogonal configuration interaction limit case. The PCFI estimation of the position of the quartet system relative to the ground state of B I will also be presented. The PCFI method leads to an impressive improvement in the convergence pattern of all the spectroscopic properties. As such, Li I, Be I and B I constitute perfect benchmarks for the PCFI method. For larger systems, it becomes hopeless to saturate a single common set of orthonormal orbitals and the PCFI method is a promising approach for getting high quality correlated wave functions. The present study constitutes a major step in the current developments of both atsp2K and grasp2K packages that adopt the biorthonormal treatment for estimating energies, isotope shifts, hyperfine structures and transition probabilities

Spin-other-orbit operator in the tensorial form of second quantization

The tensorial form of the spin-other-orbit interaction operator in the formalism of second quantization is presented. Such an expression is needed to calculate both diagonal and off-diagonal matrix elements according to an approach, based on a combination of second quantization in the coupled tensorial form, angular momentum theory in three spaces (orbital, spin and quasispin), and a generalized graphical technique. One of the basic features of this approach is the use of tables of standard quantities, without which the process of obtaining matrix elements of spin-other-orbit interaction operator between any electron configurations is much more complicated. Some special cases are shown for which the tensorial structure of the spin-other-orbit interaction operator reduces to an unusually simple form