Core-valence correlations for atoms with open shells

We present an efficient method of inclusion of the core-valence correlations into the configuration interaction (CI) calculations. These correlations take place in the core area where the potential of external electrons is approximately constant. A constant potential does not change the core electron wave functions and Green's functions. Therefore, all operators describing interaction of $M$ valence electrons and $N-M$ core electrons (the core part of the Hartree-Fock Hamiltonian $V^{N-M}$, the correlation potential $\hat\Sigma_1({\bf r},{\bf r'},E)$ and the screening of interaction between valence electrons by the core electrons $\hat\Sigma_2$) may be calculated with all $M$ valence electrons removed. This allows one to avoid subtraction diagrams which make accurate inclusion of the core-valence correlations for $M>2$ prohibitively complicated. Then the CI Hamiltonian for $M$ valence electrons is calculated using orbitals in complete $V^{N}$ potential (the mean field produced by all electrons); $\hat\Sigma_1$ + $\hat\Sigma_2$ are added to the CI Hamiltonian to account for the core-valence correlations. We calculate $\hat\Sigma_1$ and $\hat\Sigma_2$ using many-body perturbation theory in which dominating classes of diagrams are included in all orders. We use neutral Xe I and all positive ions up to Xe VIII as a testing ground. We found that the core electron density for all these systems is practically the same. Therefore, we use the same $\hat\Sigma_1$ and $\hat\Sigma_2$ to build the CI Hamiltonian in all these systems ($M=1,2,3,4,5,6,7,8$). Good agreement with experiment for energy levels and Land\'{e} factors is demonstrated for all cases from Xe I to Xe VIII.Comment: 13 pages, 5 figure

Optical transitions in highly-charged californium ions with high sensitivity to variation of the fine-structure constant

We study electronic transitions in highly-charged Cf ions that are within the frequency range of optical lasers and have very high sensitivity to potential variations in the fine-structure constant, alpha. The transitions are in the optical despite the large ionisation energies because they lie on the level-crossing of the 5f and 6p valence orbitals in the thallium isoelectronic sequence. Cf16+ is a particularly rich ion, having several narrow lines with properties that minimize certain systematic effects. Cf16+ has very large nuclear charge and large ionisation energy, resulting in the largest alpha-sensitivity seen in atomic systems. The lines include positive and negative shifters

Investigation of solid state traveling-wave- amplifier techniques for future satellite applications Quarterly progress report no. 4, 1 Mar. - 30 Jun. 1965

Solid state traveling wave amplifier techniques for satellite application

Will This Paper Increase Your h-index? Scientific Impact Prediction

Scientific impact plays a central role in the evaluation of the output of scholars, departments, and institutions. A widely used measure of scientific impact is citations, with a growing body of literature focused on predicting the number of citations obtained by any given publication. The effectiveness of such predictions, however, is fundamentally limited by the power-law distribution of citations, whereby publications with few citations are extremely common and publications with many citations are relatively rare. Given this limitation, in this work we instead address a related question asked by many academic researchers in the course of writing a paper, namely: "Will this paper increase my h-index?" Using a real academic dataset with over 1.7 million authors, 2 million papers, and 8 million citation relationships from the premier online academic service ArnetMiner, we formalize a novel scientific impact prediction problem to examine several factors that can drive a paper to increase the primary author's h-index. We find that the researcher's authority on the publication topic and the venue in which the paper is published are crucial factors to the increase of the primary author's h-index, while the topic popularity and the co-authors' h-indices are of surprisingly little relevance. By leveraging relevant factors, we find a greater than 87.5% potential predictability for whether a paper will contribute to an author's h-index within five years. As a further experiment, we generate a self-prediction for this paper, estimating that there is a 76% probability that it will contribute to the h-index of the co-author with the highest current h-index in five years. We conclude that our findings on the quantification of scientific impact can help researchers to expand their influence and more effectively leverage their position of "standing on the shoulders of giants."Comment: Proc. of the 8th ACM International Conference on Web Search and Data Mining (WSDM'15

Investigation of solid state traveling-wave amplifier techniques for future satellite applications monthly progress report no. 5, 1 - 31 jan. 1965

Solid state traveling wave amplifier techniques for satellite application

Coupled-cluster single-double calculations of the relativistic energy shifts in C IV, Na I, Mg II, Al III, Si IV, Ca II and Zn II

The relativistic coupled-cluster single-double method is used to calculate the dependence of frequencies of strong $E1$-transitions in many monovalent atoms and ions on the fine-structure constant $\alpha$. These transitions are used in the search for manifestations of the variation of the fine-structure constant in quasar absorption spectra. Results of the present calculations are in good agreement with previous calculations but are more accurate.Comment: 6 pages, 4 tables, no figures; submitted to Phys. Rev.