Effect of formic acid on O + OH˙CHOH → HCOOH + HO reaction under tropospheric condition: kinetics of and isomers.

Formic acid (HCOOH) is one of the highly abundant acids in the troposphere. It is important in the formation of atmospheric aerosols and impacts the acidity of rainwater. In the present scenario, the model chemistry of HCOOH(FA) sources and sinks is poorly understood.

Photodissociation of CHBrCHBrC(O)Cl at 248 nm: probing Br as the primary fragment using cavity ring-down spectroscopy.

The photodissociation of 2,3-dibromopropionyl chloride (CHBrCHBrC(O)Cl, 2,3-DBPC) at 248 nm was carried out to study Br as the primary molecular product in the BΠ ← XΣ transition using cavity ring-down absorption spectroscopy. The rotational spectra ('' = 0-2) were acquired and assigned with the aid of spectral simulation. It is verified that the obtained Br fragment is attributed to the one-photon dissociation of 2,3-DBPC and is free from contributions of secondary reactions.

Effect of ammonia and water molecule on OH + CHOH reaction under tropospheric condition.

The rate coefficients for OH + CHOH and OH + CHOH (+ X) (X = NH, HO) reactions were calculated using microcanonical, and canonical variational transition state theory (CVT) between 200 and 400 K based on potential energy surface constructed using CCSD(T)//M06-2X/6-311++G(3df,3pd). The results show that OH + CHOH is dominated by the hydrogen atoms abstraction from CH position in both free and ammonia/water catalyzed ones. This result is in consistent with previous experimental and theoretical studies.

Cavity Ring-Down Absorption Spectroscopy: Optical Characterization of ICl Product in Photodissociation of CHICl at 248 nm.

Iodine monochloride (ICl) elimination from one-photon dissociation of CHICl at 248 nm is monitored by cavity ring-down absorption spectroscopy (CRDS). The spectrum of ICl is acquired in the transition of BΠ ← XΣ and is confirmed to result from a primary photodissociation, that is, CHICl + hν → CH + ICl. The vibrational population ratio is determined with the aid of spectral simulation to be 1:(0.

Catalytic effect of a single water molecule on the OH + CHNH reaction.

In recent work, there has been considerable speculation about the atmospheric reaction of methylenimine (CHNH), because this compound is highly reactive, soluble in water, and sticky, thus posing severe experimental challenges. In this work, we have revisited the kinetics of the OH + CHNH reaction assisted by a single water molecule. The potential energy surfaces (PESs) for the water-assisted OH + CHNH reaction were calculated using the CCSD(T)//BH&HLYP/aug-cc-pVTZ levels of theory.