The single-reference ab initio methods for high accuracy calculations of potential energy surfaces (PESs) of excited electronic states, termed the completely renormalized equation-of-motion coupled-cluster approaches with singles, doubles, and noniterative triples [CR-EOMCCSD(T)], are developed. In the CR-EOMCCSD(T) methods, which are based on the formalism of the method of moments of coupled-cluster equations, the suitably designed corrections due to triple excitations are added, in a state-selective manner, to the excited-state energies obtained in the standard equation-of-motion coupled-cluster calculations with singles and doubles (EOMCCSD). It is demonstrated that the CR-EOMCCSD(T) approaches, which can be regarded as the excited-state analogs of the ground-state CR-CCSD(T) theory, provide a highly accurate description of excited states dominated by double excitations, excited states displaying a manifestly multireference character, and PESs of excited states along bond breaking coordinates with the ease of the ground-state CCSD(T) or CR-CCSD(T) calculations. The performance of the CR-EOMCCSD(T) methods is illustrated by the results of calculations for the excited states of CH+, HF, N2, C2, and ozone.

New coupled-cluster methods with singles, doubles, and noniterative triples for high accuracy calculations of excited electronic states.

A model of fast heating of nitrogen?oxygen mixtures excited by a gas discharge in a broad range of reduced electric fields E/N is presented. It is shown that in air at E/N ? 200?Td the main contribution to gas heating occurs due to dissociation reactions by electron impact of O2 molecules and due to processes of quenching of electronically excited N2(B?3?g, C?3?u, ) molecules by oxygen and excited O(1D) atoms by nitrogen. At E/N > 400?Td, dissociation reactions by electron impact of N2 molecules are dominant as well as the processes involving charged particles. The fraction of discharge energy converted to fast gas heating does not exceed 40%. An analysis of the experimental data on fast air heating in discharges at high reduced electric fields E/N is given.It was shown that, in a broad range of reduced electric fields, a fixed fraction of discharge power ?E spent on the excitation of electronic degrees of freedom, ionization and dissociation of molecules is converted to fast heating of nitrogen?oxygen mixtures. In air, the value of ?E is about 30 ? 3%. The value of ?E diminishes with decreasing share of oxygen in a mixture. The significant role of heat release in the pooling reactions of molecules for fast gas heating in pure nitrogen and in nitrogen with small admixtures of oxygen is demonstrated. The simulation results agree with experimental data at E/N < 200?Td within the range of oxygen content ? = 0?20%.

https://iopscience.iop.org/article/10.1088/0022-3727/44/28/285201/pdf

Fast gas heating in a nitrogen–oxygen discharge plasma: I. Kinetic mechanism

An overview is presented of experimental and theoretical research in the field of physics and engineering of singlet delta oxygen (SDO) production in low-temperature plasma of various electric discharges. Attention is paid mainly to the SDO production with SDO yield adequate for the development of an electric discharge oxygen–iodine laser (DOIL). The review comprises a historical sketch describing the main experimental results on SDO physics in low-temperature plasma obtained since the first detection of SDO in electric discharge in the 1950s and the first attempt to launch a DOIL in the 1970s up to the mid-1980s when several research groups started their activity aimed at DOIL development, stimulated by success in the development of a chemical oxygen–iodine laser (COIL). A detailed analysis of theoretical and experimental research on SDO production in electric discharge from the mid-1980s to the present, when the first DOIL has been launched, is given. Different kinetic models of oxygen low-temperature plasma are compared with the model developed by the authors. The latter comprises electron kinetics based on the accompanying solution of the electron Boltzmann equation, plasma chemistry including reactions of excited molecules and numerous ion–molecular reactions, thermal energy balance and electric circuit equation. The experimental part of the overview is focused on the experimental methods of SDO detection including experiments on the measurements of the Einstein coefficient for SDO transition and experimental procedures of SDO production in self-sustained and non-self-sustained discharges and analysis of different plasma-chemical processes occurring in oxygen low-temperature plasma which brings limitation to the maximum SDO yield and to the lifetime of the SDO in an electric discharge and its afterglow. Quite recently obtained results on gain and output characteristics of DOIL and some projects aimed at the development of high-power DOIL are discussed.

https://iopscience.iop.org/article/10.1088/0022-3727/40/2/R01/pdf

Physics and engineering of singlet delta oxygen production in low-temperature plasma

High-density-plasma deposition of SiO2 is an important process in integrated circuit manufacturing A list of gas-phase and surface reactions has been compiled for modeling plasma-enhanced chemical vapor deposition of SiO2 from SiH4, O2, and Ar gas mixtures in high-density-plasma reactors The gas-phase reactions include electron impact, neutral–neutral, ion–ion, and ion–neutral reactions The surface reactions and deposition mechanism is based on insights gained from attenuated total reflection Fourier transform infrared spectroscopy experiments and includes radical adsorption onto the SiO2 surface, ion-enhanced desorption from the surface layer, radical abstractions, as well as direct ion-energy-dependent sputtering of the oxide film A well-mixed reactor model that consists of mass and energy conservation equations averaged across the reactor volume was used to model three different kinds of high-density plasma deposition chambers Experimental measurements of total ion densities, relative radical dens

Modeling of SiO2 deposition in high density plasma reactors and comparisons of model predictions with experimental measurements

Isotope effects in the chemistry of atmospheric trace compounds.

Spectroscopic data and reaction rate coefficients pertinent to ozone in the mesosphere and thermosphere (altitude >50 km) are critically surveyed. These data should be of use in modeling atmospheric infrared luminescence, measuring atmospheric ozone concentrations by remote sensing, and designing and interpreting laboratory measurements. There is a clear need for additional data on metastable ozone electronic states, additional atmospheric ozone formation channels, collision processes involving electrons and ions, and vibrational state dependence of reaction rate coefficients.

Jean W. Gallagher

Papers

Critical Survey of Data on the Spectroscopy and Kinetics of Ozone in the Mesosphere and Thermosphere