Formation of the ground-state nitrogen atom, N((4)S), following 193.3-nm ArF laser irradiation of NO and NO(2) was detected directly by a technique of laser-induced fluorescence (LIF) spectroscopy at 120.07 nm. Tunable vacuum ultraviolet (VUV) laser radiation around 120.07 nm was generated by two-photon resonance four-wave sum frequency mixing in Hg vapor. Photoexcitation processes of NO and NO(2) giving rise to the N((4)S) formation are discussed on the basis of the Doppler profiles of the nascent N((4)S) atoms produced from the photolysis of NO and NO(2) and the photolysis laser-power dependence of the N((4)S) signal intensities. Using laser flash photolysis and vacuum ultraviolet laser-induced fluorescence detection, the kinetics of the reactions of N((4)S) with NO and NO(2) have been investigated at 295 +/- 2 K. The rate constants for the reactions of N((4)S) with NO and NO(2) were determined to be (3.8 +/- 0.2) x 10(-11) and (7.3 +/- 0.9) x 10(-12) cm(3) molecule(-1) s(-1), respectively, where the quoted uncertainties are 2sigma statistical uncertainty including estimated systematic error.
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http://dx.doi.org/10.1021/jp054089c | DOI Listing |
Molecules
October 2024
Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
Three-body recombination reactions, in which two particles form a bound state while a third one bounces off after the collision, play significant roles in many fields, such as cold and ultracold chemistry, astrochemistry, atmospheric physics, and plasma physics. In this work, the dynamics of the recombination reaction for the N system over a wide temperature range (5000-20,000 K) are investigated in detail using the quasi-classical trajectory (QCT) method based on recently developed full-dimensional potential energy surfaces. The recombination products are N() + N() in the 1″ state, N() + N() in the 2″ state, and N() + N() in both the 1″ and 2″ states.
View Article and Find Full Text PDFJ Phys Chem A
August 2024
Instituto de Plasmas e Fusão Nuclear (IPFN), Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal.
This work presents a detailed investigation aimed at understanding the key mechanisms governing nitric oxide (NO) production in N-O discharges by systematically comparing experimental results to modeling data. The experimental phase capitalizes on radiofrequency (13.56 MHz) discharges, sustained at 5 mbar pressure conditions, featuring varying concentrations of oxygen, ranging from pure N plasma to air-like mixtures.
View Article and Find Full Text PDFJ Phys Chem A
October 2024
Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland.
The atom-exchange and atomization dissociation dynamics for the N(S) + N(Σ) reaction are studied using a reproducing kernel Hilbert space (RKHS)-based, global potential energy surface (PES) at the MRCI-F12/aug-cc-pVTZ-F12 level of theory (MRCI, multireference configuration interaction). For the atom exchange reaction (NN + N → NN + N), computed thermal rates and their temperature dependence from quasi-classical trajectory (QCT) simulations agree to within error bars with the available experiments. Companion QCT simulations using a recently published CASPT2-based PES confirm these findings.
View Article and Find Full Text PDFJ Chem Phys
July 2024
Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
Excited atomic nitrogen atoms play an important role in plasma formation in hypersonic shock-waves, as happens during spacecraft reentry and other high velocity vehicle applications. In this study, we have thoroughly studied collision induced excitation associated with two colliding nitrogen atoms in the N(4S), N(2D), and N(2P) states at collision energies up to 6 eV, using time-independent scattering calculations to determine cross sections and temperature-dependent rate coefficients. The calculations are based on potential curves and couplings determined in earlier multireference configuration interaction calculations with large basis sets, and the results are in good agreement with experiments where comparisons are possible.
View Article and Find Full Text PDFHealthcare (Basel)
May 2024
Department of Health and Society & Wilson Centre for Health Professions Education Research, University of Toronto, 1265 Military Trail, Toronto, ON M1C1A4, Canada.
Introduction: Paramedic practice is highly variable, occurs in diverse contexts, and involves the assessment and management of a range of presentations of varying acuity across the lifespan. As a result, attempts to define paramedic practice have been challenging and incomplete. This has led to inaccurate or under-representations of practice that can ultimately affect education, assessment, and the delivery of care.
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