Related papers: Improved He I Emissivities in the Case B Approxima…
Precision measurements of the cosmic microwave background temperature anisotropy on scales $\ell > 500$ will be available in the near future. Successful interpretation of these data is dependent on a detailed understanding of the damping…
We present the first detailed ab initio quantum mechanical calculations for total and state-specific recombination rate coefficients for e + Ni III --> Ni II. These rates are obtained using a unified treatment for total electron-ion…
We present a refined treatment of H, He I, and He II recombination in the early Universe. The difference from previous calculations is that we use multi-level atoms and evolve the population of each level with redshift by including all…
A study of emission temperatures extracted from excited state populations and of freeze out radii from light particle intensity interferometry is presented. Three high resolution dE-E-Hodoscopes with a total of 216 detectors are combined…
We have measured the differential cross section for the $\gamma$$^3$He$\rightarrow \pi^+ t$ reaction. This reaction was studied using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. Real photons produced with the Hall-B…
We investigate experimentally and theoretically the electron emission in collisions between He atoms and Li$^{q+}$ (q=1,2) projectiles at intermediate-high incident energies. We report on measured absolute values of double differential…
Aimed at ionization balance and spectral analysis of UV and X-ray sources, we present self-consistent sets of photoionization cross sections, recombination cross sections, and rate coefficients for Li-like O VI and He-like O VII.…
We have studied finite temperature corrections to the baryon transport cross sections and diffusion coefficients. These corrections are based upon the recently computed renormalized electron mass and the modified state density due to the…
We have reanalyzed SUMER observations of a parcel of coronal gas using new collisional ionization equilibrium (CIE) calculations. These improved CIE fractional abundances were calculated using state-of-the-art electron-ion recombination…
Cross sections are presented for dissociative recombination and electron-impact vibrational excitation of the ArH+ molecular ion at electron energies appropriate for the interstellar environment. The R-matrix method is employed to determine…
Previously a compact formula for total reaction cross section for heavy-ion collisions as a function of energy was obtained by treating the angular momentum $l$ as a continuous variable. The accuracy of the continuum approximation is…
We present new calculations and analytic fits to the rates of radiative recombination towards H-like, He-like, Li-like and Na-like ions of all elements from H through Zn (Z=30). The fits are valid over a wide range of temperature, from 3 K…
The basic approach for measuring electron-ion recombination rate coefficients in merged-beams electron-ion collision experiments at heavy-ion storage rings is outlined. As an example experimental results for the low temperature…
The modelling of emission spectra of molecules seen in interstellar clouds requires the knowledge of collisional rate coefficients. Among the commonly observed species, N$_2$H$^+$ is of particular interest since it was shown to be a good…
We present comprehensive \textsl{ab initio} calculations of CO$_{\rm 2}$-H$_{\rm 2}$ and CO$_{\rm 2}$-He collisional properties from first principles, employing CCSD(T), potential calculations together with close-coupling dynamical…
The theoretical intensities of the soft X-ray Fe XVII lines arising from 2l-3l' transitions are reexamined using a three-ion collisional-radiative model that includes the contributions to line formation of radiative recombination (RR),…
In calculations of the ionization state, one is often forced to choose between the Case A recombination coefficient $\alpha_{\rm A}$ (sum over recombinations to all hydrogen states) or the Case B recombination coefficient $\alpha_{\rm B}$…
The logarithmic extinction coefficient, c(H$\beta$), is usually derived using the H$\alpha$/H$\beta$ ratio for case B recombination and assuming standard values of electron density and temperature. However, the use of strong Balmer lines…
We present improved fits to our treatment of suppression of dielectronic recombination at intermediate densities. At low densities, most recombined excited states eventually decay to the ground state, and therefore the total dielectronic…
We compute the thermal photon spectrum in the Pb+Pb collisions at the CERN SPS energy using thermal emission rates and a hydrodynamic description for the evolution of produced hot matter and compare our results with the measurements of the…