Quantum chemical study of the structure, spectroscopy and reactivity of NO ⁺ .(H ₂ O) _{n =1−5} clusters

Abstract

Quantum chemical methods including Møller-Plesset perturbation (MP2) theory and density functional theory (DFT) have been used to study the structure, spectroscopy and reactivity of NO(HO) clusters. MP2/6-311++G** calculations are shown to describe the structure and spectroscopy of the clusters well. DFT calculations with exchange-correlation functionals with a low fraction of Hartree-Fock exchange give a binding energy of NO(HO) that is too high and incorrectly predict the lowest energy structure of NO(HO), and this error may be associated with a delocalization of charge onto the water molecule directly binding to NO Ab initio molecular dynamics (AIMD) simulations were performed to study the NO(HO) [Formula: see text] H(HO) + HONO reaction to investigate the formation of HONO from NO(HO) Whether an intracluster reaction to form HONO is observed depends on the level of electronic structure theory used. Of note is that methods that accurately describe the relative energies of the product and reactant clusters did not show reactions on the timescales studied. This suggests that in the upper atmosphere the reaction may occur owing to the energy present in the NO(HO) complex following its formation.This article is part of the theme issue 'Modern theoretical chemistry'.

Noncovalent Interactions in Hydrated Nitrosonium Ion Clusters Mediated by Hydrogen-Bonded Water Networks

“…Hydrated nitrosonium ion clusters [NO + (H 2 O) n ] play crucial roles in the ion processes of the D region in the ionosphere, and they are also archetypal and concise models to present effects of different solvation shells. − Therefore, molecular structures, energies, vibrational spectra, and reactivities of the NO + (H 2 O) n clusters have been sustainedly investigated in depth to enrich understandings on the atmospheric ion chemistry of the D region in the ionosphere. − …”

“…As mentioned above, previous works − mainly focused on reaction mechanisms for the HONO formation in the NO + (H 2 O) n clusters. Additionally, charge transfer characters were also qualitatively analyzed for the NO + (H 2 O) 3 isomers .…”

Interplay of Hydrogen, Pnicogen, and Chalcogen Bonding in X(H2O)n=1–5 (X = NO, NO+, and NO–) Complexes: Energetics Insights via a Molecular Tailoring Approach

“…10,21−23 The relative energies of these complexes are consistent with the previously reported structures. 10,23 As can be seen from Figure S2, NO interacts with water through PB in all isomers of the NO + (H 2 O) n=1−5 complexes. Moreover, in few isomers (3C + , 3E + , 4D + , 4F + , 4H + , 5A + , 5B + , 5C + , 5E + , 5F + , 5G + , and 5J + ) of NO + (H 2 O) n=3−5 complexes, the O atom of NO + also interacts with O atom of H 2 O.…”

“…21 Similarly, there are some successful attempts to study the intracluster reaction of NO + (H 2 O) n systems. 22,23 The microhydration of NO − with water cluster also generates significant interest among researchers. 20,24 In a previous study, Eaton et al recorded the photoelectron spectrum of NO − (H 2 O) 2 complexes.…”

Modern theoretical chemistry: the legacy of Prof. John N. Murrell

“…Accuracy is also central to calculations presented in work by Mizus et al [3] where a new potential energy surface for the water molecule is used to generate a set of improved transition intensities for selected ro-vibrational transitions-work that reflects the significance of the water molecule in the search of life on other planets. The chemical role played by water molecules in the Earth's upper atmosphere is illustrated in the contribution by Linton et al [4], where ab initio methods have been used to study the reaction between NO + and small numbers of water molecules. One of the products, a protonated water cluster, has long been proposed as a precursor to cloud formation at very high altitudes.…”