A theoretical study of the microhydration processes of iodine nitrogen oxides

Abstract

This work reports for the first time the structures and the thermodynamics of the microhydrates of iodine nitrogen oxides (INO x ). Monohydrates and dihydrates were investigated for five different INO x species (INO, INO 2 , cis-IONO, trans-IONO, and IONO 2 ). The structures of the water complexes were characterized at the ωB97XD/aug-cc-pVTZ level of theory. Coupled-cluster calculations were performed with the ANO-RCC-VQZP basis sets. Standard reaction enthalpy and standard Gibbs free reaction energy (Δ r G 298 K ) were computed for all aggregates. The variation of Δ r G[T] as a function of temperature reveals that only IONO 2 will be hydrated at tropospheric temperatures (T < 270 K). Its dihydration reaction remains a favored process in the same conditions. All INO x species will not be hydrated in gas phase in the containment building of a pressurized water reactor for which temperatures are greater than 400 K.

Unraveling the Tropospheric Microhydration Processes of Iodous Acid HOIO

“…This difference is increasing when adding more water molecules to the aggregates. These variations are close to the ones noticed in the iodine nitroxides microhydration processes . When considering the most stable molecular complex in terms of standard Gibbs free energy at 298 K, we observed that the monohydration of HOIO is characterized by Δ r G ° 298K > 0 at the DK-CCSD­(T)-cf level, while the next hydration reactions ( n = 2, 3, 4) exhibit negative Gibbs free energies.…”

“…Optimized geometry parameters and vibrational frequencies for H 2 O at the ωB97X-D/aug-cc-pVTZ level of theory have been already presented in our last studies. , The corresponding data for iodous acid are presented in Tables S1 and S2 of the Supporting Information. Comparison with the previous data obtained by Khanniche et al at the B3LYP/aug-cc-pVTZ level of theory shows slight differences between the bond lengths (<0.034 Å) and angles (<1°).…”

Theoretical Study of the Monohydration of Mercury Compounds of Atmospheric Interest

“…Optimized geometric parameters and vibrational frequencies for H 2 O at the ωB97X-D/aug-cc-pVTZ level have been already presented in previous studies. − The BrHgO geometry was previously computed by Balabanov et al, at CCSD­(T)/CBS, and our geometry compares well with their results. For HOHg, our HgO bond length is also longer (by 0.038 Å) than that computed by Dibble et al, at the CCSD­(T,full)/AwCVTZ level.…”

Theoretical treatment of IO–X (X = N2, CO, CO2, H2O) complexes

“…At the RCCSD(T)/CBS, we compute BEs (in kcal mol −1 ) of −1.541 for OI–N 2 and −0.768 for IO–N 2 , of −1.260 for OI–CO and of −1.051 for IO–CO, of −2.079 for OI–CO 2 and −1.974 for IO–CO 2 , and of −4.991 for OI–H 2 O and −2.738 for IO–H 2 O. The presently found over stability of the halogen bonded complexes vs. the hydrogen bonded complexes was already noticed for IO–Ar, 28 for monohydrates of IO, 34,59 of ClO, 72 of BrO, 72 of INO, 73 and of INO 2 , 73 for hypoiodous acid interacting with CO ( i.e. HOI–CO) 74 and for hypoiodous acid interacting with NH 3 ( i.e.…”