Chemical dynamics study on the gas-phase reaction of the D1-silylidyne radical (SiD; X²Π) with deuterium sulfide (D₂S) and hydrogen sulfide (H₂S)

Abstract

Center-of-mass velocity flux contour map for the reaction of the D1-silylidyne radical (SiD) with deuterium sulfide (D2S) leading to the gas-phase formation of D2-silanethione (D2SiS).

Low-Temperature Gas-Phase Formation of Methanimine (CH2NH; X1A′)─the Simplest Imine─under Single-Collision Conditions

“…Note that our experiments utilized the D1-methylidyne radical, but calculations were conducted for the methylidyne radical. However, as proposed in multiple reactions, ,, due to the difference in zero point energies, the difference in energetics of the intermediates, transition state, and products of reaction systems with (partially) deuterated or nondeuterated reactants should be less than 5 kJ mol –1 ; this discrepancy lies within the experimental uncertainties of our results. Two products can be formed in exoergic reactions: p1 (CHDNH; D1-methanimine; −239 kJ mol –1 ; X 1 A′) and p2 (CDNH 2 ; D1-aminomethylene; −90 kJ mol –1 ; X 1 A′).…”

Gas-Phase Study of the Elementary Reaction of the D1-Ethynyl Radical (C2D; X2Σ+) with Propylene (C3H6; X1A′) under Single-Collision Conditions

“…Reactions of the D1-ethynyl radical (C 2 D, X 2 Σ + ) with propylene (C 3 H 6 , ≥99%, Sigma–Aldrich) and of D3–3,3,3-propylene (C 2 H 3 CD 3 , 99.8% D atom, CDN Isotopes) were performed under single collision conditions utilizing a crossed molecular beams apparatus. − Briefly, a pulsed supersonic beam of D1-ethynyl radicals was generated by laser ablation of a rotating carbon rod with 5–7 mJ of the 266 nm output of a Nd:YAG laser (Quanta-Ray Pro 270, Spectra-Physics); the ablated species subsequently reacted with neat deuterium gas (D 2 , 99.999%, Linde), which passed through a Proch-Trickl pulsed valve with an open time of 80 μs at an amplitude of −400 V. Deuterium also acted as a carrier gas with a backing pressure of 4 atm. ,,,, The pulsed beam passed through a skimmer and the velocity was selected by a chopper wheel resulting in a peak velocity ( v p ) of 2136 ± 19 m s –1 and a speed ratio ( S ) of 5.5 ± 0.3. Since the travel time of D1-ethynyl radicals from the ablation center to the interaction region was ∼30 μs, any species in the A 2 Π excited state, which has a lifetime of <1 μs, relaxed back to the X 2 Σ + ground state.…”

Formation of Thioformic Acid (HCOSH)─The Simplest Thioacid─in Interstellar Ice Analogues

“…These representative molecules are frequently used as tracers for the kinematics and chemical evolution of star- and planet-forming regions . The detections of sulfur-bearing molecules motivate laboratory experiments on sulfur-containing interstellar ice analogues under simulated astrophysical conditions, which commonly involve reactions with atomic hydrogen, , thermal processing, , radiolysis with energetic electrons, protons, and helium ions, photolysis exploiting photons ranging from visible light to X-rays, , and neutral–neutral gas-phase reactions. ,, However, it is not yet clear in which forms most of the sulfur resides in molecular clouds . To solve this ″missing sulfur″ problem, systematic experimental studies under controlled chemical and physical conditions such as temperature, ice morphology, projectile ion-charge state, and energy are much needed …”