∆SCF Dyson Orbitals and Pole Strengths from Natural Ionization Orbitals

The calculation of photoionization cross-sections can play a key role in spectral assignments using modeling and simulation. In this work, we provide formal relationships between pole strengths, which are proportional to the photoionization cross-section, and terms related to the Natural Ionization Orbital model for Delta-SCF calculations. A set of numerical calculations using the developed models is carried out. Pole strength values computed using the two approaches developed for Delta-SCF calculations demonstrate excellent agreement with an electron propagator theory model.

∆SCF Dyson Orbitals and Pole Strengths from Natural Ionization Orbitals

The calculation of photoionization cross-sections can play a key role in spectral assignments using modeling and simulation. In this work, we provide formal relationships between pole strengths, which are proportional to the photoionization cross-section, and terms related to the Natural Ionization Orbital model for Delta-SCF calculations. A set of numerical calculations using the developed models is carried out. Pole strength values computed using the two approaches developed for Delta-SCF calculations demonstrate excellent agreement with an electron propagator theory model.

NON-UNIVERSALITY AND EVOLUTION OF THE SIVERS FUNCTION

We examine the large-x QCD evolution of the twist-three gluonic-pole strength defining an effective T -odd Sivers function, where evolution of the T -even transverse-spin DIS structure function g2 is multiplicative. The result corresponds to a colour-factor modified spin-averaged twist-two evolution.

The breakdown of superfluidity in liquid 4 He. II. An investigation of excitation emission from negative ions travelling at extreme supercritical velocities

We have measured the drift velocity, v, of negative ions in He II at a temperature of 0.34 K and a pressure of 25 bar¶ for electric fields, E , in the range 5 x 10 3 < E < 6 x 10 6 V m -1 . For v <70 m s -1 , the results are in good agreement with the predictions of the roton pair-emission theory of Bowley & Sheard. Even better agreement is obtained by extending the theory to take explicit account of departures from parabolicity of the real dispersion curve at large momenta, variations in the pole strength of high momentum excitations, and the slight increase in the average momentum of excitations emitted at large values of v. For v> 70 m s -1 , however, experiment and theory are in clear disagreement: by v = 80 m s -1 , the measured drag on the ion has become about 100 % larger than the theoretical prediction. We tentatively attribute this discrepancy to the onset at v« 70 m s -1 of a new and, so far, unidentified dissipation mechanism.