The C(³P) + O₂(³Σ_g⁻) → CO₂ ↔ CO(¹Σ⁺) + O(¹D)/O(³P) reaction: thermal and vibrational relaxation rates from 15 K to 20 000 K

Abstract

Thermal rates for the C(3P) + O2(3Σ-g) ↔ CO(1Σ+)+ O(1D)/O(3P) reaction are investigated over a wide temperature range based on quasi classical trajectory (QCT) simulations on 3-dimensional, reactive potential energy...

Genesis of Polyatomic Molecules in Dark Clouds: CO2 Formation on Cold Amorphous Solid Water

“…Early emission spectra found that the C( 3 P) + O 2 ( 3 Σ g − ) reaction generates CO with v′ = 17 and that the transition state has the COO configuration rather than OCO. 43 As both the high-level CCSD(T)-F12 PES and a recently determined MRCISD+Q/aug-cc-pVTZ ground state PES 12 support stabilization of the COO structure, the present results also indicate that association of CO with O( 1 D) can lead to formation and stabilization of COO. Complementary to the O( 1 D) + CO( 1 Σ + ) reaction considered here, the O( 3 P) + CO( 1 Σ + ) process to yield triplet (excited) CO 2 is also feasible.…”

“…9 Such a process has also been proposed to occur on interstellar grains 10 and has been confirmed experimentally 11 with an estimated entrance barrier of 0.014−0.103 eV for the process on ASW, compared with a value of 0.3 eV from high-level electronic structure calculations. 12 The surrounding water matrix provides the necessary coupling 8 to facilitate relaxation of the 3 A′ or 3 A″ states of CO 2 to the 1 A′ ground state (correlating with linear 1 Σ g + ). On the other hand, the presence of an entrance barrier for the O( 3 P) + CO( 1 Σ + ) reaction has one led to consider the alternative CO + OH pathway for CO 2 formation 13 which was, however, reconsidered to yield the HOCO intermediate in such environments in more recent experiments.…”

“…Such a COO intermediate has been proposed from the interpretation of the C + O 2 reaction 30 and was also found in calculations. 12,31 The two For each of the initial conditions, between 100 and 1000 independent trajectories were run; see Tables S1, S2, and S3. In total, 32500 simulations were run to determine the probability and rate for CO 2 formation depending on the initial conditions.…”

“…Also, the validity of QCT-based simulations has been explicitly validated for the [CNO] reactive system by comparing final vibrational state distributions with time-independent quantum simulations. 41 The efficiency of nonadiabatic effects due to O( 1 D) to O( 3 P) conversion have been estimated 12 to be 10% at 300 K based on earlier measurements. 42 This may change at lower temperature, though, and explicit inclusion of nonadiabatic processes for the O( 1 D) + CO association reaction to form CO 2 appears to be of interest in the future.…”

High-Resolution Imaging of C + He Collisions using Zeeman Deceleration and Vacuum-Ultraviolet Detection

“…Noteworthy species like OH, CO, NH 3 , and CH 3 possess well-known VUV transitions, 47−50 although for some the intermediate state is strongly predissociative, and it remains to be seen how efficient and state-selective near-threshold multicolor REMPI schemes are best implemented for these species. Furthermore, making use of the recently reported near-threshold VUV-based REMPI schemes for H/D 51 or O( 3 P) atoms, 52 our approach provides a pathway to high-resolution and low-energy investigations of elementary reactive scattering processes that produce O or H atoms, such as C + O 2 → CO + O 35,53,54 or complex-forming reactions between Zeeman decelerated atoms and H 2 molecules. 55−57…”