Electron collisions with the CF radicals using the R-matrix method

The R-matrix method is used to treat electron collisions with the diatomic radical CF as a function of internuclear separation, R. These calculations concentrate on obtaining low-energy (< 10 eV) elastic and excitation cross sections of the five lowest-lying electronically excited states of the symmetries X2 Π, 4 Σ-, 2 Σ+, 2Δ, 2 Σ- and 4 Π, with vertical excitation energies in the range of 2.86–10 eV. Special measures are required to treat 2 Σ+, which is Rydberg-like for R < 2.6 a0. Three shape resonances of 3Σ-,1 Δ and 1 Σ+ symmetries are fitted. The 1 Δ and 1 Σ+ resonances have a position of 0.91 and 2.19 eV respectively at the equilibrium bond length of CF. The position of the 3 Σ- resonance is close to zero at Re = 2.44 a0 and the resonance becomes bound at larger R. Two weakly bound states of symmetries 3Π and 1 Π were also detected at the equilibrium geometry. Calculations which stretch the C–F bond show that the 1Δ resonance becomes bound at R = 3.3 a0 and 1 Σ+ at larger R

Elastic differential cross sections for the CFx (x = 1, 2, 3) radicals

Theoretical rotationally summed elastic differential cross sections for scattering of electrons by CFx radicals (x = 1–3) in the low-energy range (below 10 eV) are reported. The calculations used close-coupled expansions with target wavefunctions modelled using complete active space configuration interaction. The body-fixed K-matrices, used to calculate differential cross sections, were generated using the UK R-matrix codes. Comparison of the present results with existing theoretical data for electron collisions with CF and CF3 radicals is made

Comparison of SABER OH Measurements to Rocket Photometry Data

In 2002, the Sounding of the Atmosphere us- ing Broadband Emission Radiometry (SABER) instru- ment aboard the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite went online and has since been providing radiometric data concern- ing the mesosphere and lower thermosphere/ionosphere (MLTI) region of the atmosphere. Researchers at the Utah State University NASA Space Grant Consortium have been tasked with validating measurements of the hydroxyl airglow volume emission rates (VER) taken by SABER. To this end, we compare SABER measurements of the altitude distribution of hydroxyl airglow to mea- surements taken by photometers aboard rockets launched between 1961 and 1986 that were catalogued in 1988 by Baker and Stair [1]. We select for comparison SABER scans taken near these launch sites at the same time of year, and at similar solar zenith angles. We then plot the selected SABER altitude profiles alongside renormalized rocket photometer profiles. Important considerations for comparison are the mean thickness of emission layers, the mean altitude of their centers, and relative numbers of bifurcated airglow emission layers, which manifest as altitude profiles with two or more peaks

Electron molecule collisions calculations using the R-matrix method

The R-matrix method provides a complete theoretical framework for the treatment of low energy electron collisions. Recent results obtained with the UK R-matrix codes are presented focusing on electron impact electronic excitation of water and the CF radical, electron impact dissociation of molecular hydrogen and its isotopomers, and the dissociative recombination of the CO2+ dication. Examples of other processes, studied in recent calculations are also given. (C) 2003 Elsevier Science Ltd. All rights reserved

Low and intermediate energy electron collisions with the C2−_2^- molecular anion

Calculations are presented which use the molecular R-matrix with pseudo-states (MRMPS) method to treat electron impact electron detachment and electronic excitation of the carbon dimer anion. Resonances are found above the ionisation threshold of C$_2^-$ with $^1\Sigma^+_g$, $^1\Pi_g$ and $^3\Pi_g$ symmetry. These are shape resonances trapped by the effect of an attractive polarisation potential competing with a repulsive Coulomb interaction. The $\Pi_g$ resonances are found to give structure in the detachment cross section similar to that observed experimentally. Both excitation and detachment cross sections are found to be dominated by large impact parameter collisions whose contribution is modelled using the Born approximation.Comment: 18 pages, 5 figures constructed from 8 file

Quantemol-N: an expert system for performing electron molecule collision calculations using the R-matrix method

The R-matrix method has been widely employed to ab initio calculations on a large variety of problems related to electron molecule scattering. The UK Molecular R-matrix Code, which are a synthesis between codes designed for quantum chemistry and electron atom scattering calculations, has proved particularly popular for these studies but is difficult for the non-specialist to use. The Quantemol-N software environment is designed for scientists with a minimal knowledge of scattering theory or quantum chemistry to use without the need of a complex and dedicated training. Their use is illustrated for low energy electron collisions with silane

The influence of dependences of psychophysiological characteristics of drivers

The article analyzes the "man-machine-environment" system in relation to the psychophysiological characteristics of the driver - "human operator". The methods of diagnosing the psychophysiological characteristics of drivers were analyzed. The dependencies between the parameters of psychophysiological characteristics were established: complex visual-motor reaction and emotional stability (Pearson correlation coefficient r = -0.7), as well as the correlation between emotional stability and the level of perception of speed and distance (r = 0.5). The psychophysiological characteristics at different stages of the driving experience were revealed and practical recommendations were formulated for their development