相关论文: Modeling of Collision-Induced Excitation and Quenc…
We report a combined experimental and theoretical study of collision-induced dipolar relaxation in a cold spin-polarized gas of atomic nitrogen (N). We use buffer gas cooling to create trapped samples of 14N and 15N atoms with densities…
In order to interpret and predict the behavior and properties of fusion plasma, accurate cross sections for electronic processes in collisions between plasma impurities and atomic hydrogen are required. In this work, we investigate the…
Using a quantum-mechanical close-coupling method, we calculate cross sections for fine structure excitation and relaxation of Si and S atoms in collisions with atomic hydrogen. Rate coefficients are calculated over a range of temperatures…
Emission lines from highly-excited states (n >= 5) of H- and He-like ions have been detected in astrophysical sources and fusion plasmas. For such excited states, R-matrix or distorted wave calculations for electron-impact excitation are…
Nitric oxide is an open-shell molecule abundantly detected in the interstellar medium. A precise modeling of its radiative and collisional processes opens the path to a precise estimate of its abundance. We present here the first rate…
The availability of collisional rate coefficients is a prerequisite for an accurate interpretation of astrophysical observations, since the observed media often harbour densities where molecules are populated under non--LTE conditions. In…
The vibrational quenching cross sections and corresponding low-temperature rate constants for the v = 1 and v = 2 states of CN- colliding with He and Ar atoms have been computed ab initio using new three dimensional potential energy…
Fine-structure transitions can be involved in various processes including photon absorption, charge transfer and inelastic collision between ions, electrons and neutral atoms. We present fine-structure excitation and relaxation cross…
Ammonia is one of the most widely observed molecules in space, and many observations are able to resolve the hyperfine structure due to the electric quadrupole moment of the nitrogen nucleus. The observed spectra often display anomalies in…
Modeling environments that are not in local thermal equilibrium, such as protoplanetary disks or planetary atmospheres, with molecular spectroscopic data from space telescopes requires knowledge of the rate coefficients of rovibrationally…
We explore the quantum dynamics of nuclear spin relaxation in cold collisions of $^1\Sigma^+$ molecules with structureless atoms in an external magnetic field. To this end, we develop a rigorous coupled-channel methodology, which accounts…
We consider the degree of conservation of nuclear spin polarization in the process of optical pumping under typical spin-exchange optical pumping conditions. Previous analyses have assumed that negligible nuclear spin precession occurs in…
There have been discussions in the recent literature regarding the accuracy of the available electron impact excitation rates (equivalently effective collision strengths $\Upsilon$) for transitions in Be-like ions. In the present paper we…
Utilising previous work by the authors on the spin-coupled rotational cross-sections for electron-CN collisions, data for the associated rate coefficients is presented. Data on rotational, fine-structure and hyperfine-structure transition…
Resonant vibrational excitation cross sections and the corresponding rate coefficients for electron-N$_2$ collisions occurring through the N$_2^-(\textrm{X}\ ^2\Pi_g)$ resonant state are reviewed. New calculations are performed using…
Whereas collisions between atoms and molecules are largely understood, collisions between two molecules have proven much harder to study. In both experiment and theory, our ability to determine quantum state-resolved bimolecular cross…
Electron-impact vi->vf vibrational excitations cross sections, involving rovibrationally excited N_{2}(v_{i}, J) and NO(v_{i}, J) molecules (fixed J), are calculated for collisions occurring through the nitrogen resonant electronic state…
The introduction of gases like nitrogen or neon for cooling the edge region of magnetically confined fusion plasmas has triggered a renewed interest in state selective cross sections necessary for plasma diagnostics by means of charge…
Recent observation and analysis of kilonovae (KNe) spectra as a result of neutron star mergers require accurate and complete atomic structure and collisional data for interpretation. Ideally, the atomic datasets for elements predicted to be…
This study investigates the ionization and excitation processes induced by electron impact between two configurations or superconfigurations. Rate coefficients are calculated for transition arrays or super-transition arrays rather than…