Ortho-para interconversion of nuclear states of H2O through replica transition state: prospect of quantum entanglement at homodromic Bjerrum defect site

Abstract

Context From a nuclear spin prospective, water exists as para and ortho nuclear spin isomers (isotopomers). Spin interconversions in isolated molecules of water are forbidden, but many recent reports have shown them to happen in bulk, through dynamic proton exchanges happening between interconnected networks of a large array of water molecules. In this contribution, a possible explanation for an unexpected slow or delayed interconversion of ortho-para water in ice observed in an earlier reported experiment is provided. Using the results of quantum mechanical investigations, we have discussed the roles played by Bjerrum defects in the dynamic proton exchanges and ortho-para spin state interconversions. We guess that at the sites of the Bjerrum defects, there are possibilities of quantum entanglements of states, through pairwise interactions. Based on the perfectly correlated exchange happening via a replica transition state, we speculate that it can have significant influences on ortho-para interconversions of water. We also conjecture that the overall ortho-para interconversion is not a continuous process, rather can be imagined to be happening serendipitously, but within the boundary of the rules of quantum mechanics. Methods All computations were performed with Gaussian 09 program. B3LYP/6-31++G(d,p) methodology was used to compute all the stationary points. Further energy corrections were computed using CCSD(T)/aug-cc-pVTZ methodology. Intrinsic reaction coordinate (IRC) path computations were carried out for the transition states.

Better performances of benzene‐based over thiophene‐based aromatic anionic donors: Computational studies on metameric conformational selectivity and hyperpolarizability of organic inner salts

“…As we observed, in DFT methodologies, while going from CAM‐B3LYP and ωB97xD methodologies (long‐range and/or dispersion corrections), HLGs were found to be advancing more toward the HF values, in all the four molecules. To account for these behaviors, a quick search in the literature showed many interesting works, pointing toward localization–delocalization issues associated with the HF and DFT methodologies (overlocalization of HF and overdelocalization of DFT methodologies) 91 . As the current work is not focused on exploring these aspects in detail, interested readers can refer to the recent article (perspective) of Kulik 102 (for a more in‐depth understanding of the issues).…”

“…Even in some of our recent works, we observed that these methodologies are suitable in describing charge separated molecular systems like the zwitterions 91–93 . For all the methodologies, a reasonably good basis set like 6‐31++G(d,p) was used, as such a basis set considers polarization and diffusion functions and is suitable for charge separated molecular systems like the zwitterions considered here 91 . As metameric influences on conformational preferences were focus, hence, no symmetry restrictions were imposed during the optimizations.…”

“…Choices of these methodologies are based on some earlier reports, where effects of electron correlations as well as effects of long‐range corrections were investigated for nonlinear optical properties and are suggested as suitable methodologies 85–90 . Even in some of our recent works, we observed that these methodologies are suitable in describing charge separated molecular systems like the zwitterions 91–93 . For all the methodologies, a reasonably good basis set like 6‐31++G(d,p) was used, as such a basis set considers polarization and diffusion functions and is suitable for charge separated molecular systems like the zwitterions considered here 91 .…”

Not fully twisted, not fully planar, but intermediate torsions for ideal chromophore design: A computational study on p‐phenylene bridged pyridinium phenolate betaines

“…A recent work by Kulik [88] (a prospective article) highlights such recent developments on various inadequacies associated with the DFT. Recently, I have also used this concept successfully to explain the better performance of HF over DFT, for similar zwitterions [89]. Here also, for M1 and M2, using the concepts of localization/delocalization, one can easily explain the observed trends with respect to various methodologies.…”