1
|
Sitha S. Ortho-para interconversion of nuclear states of H 2O through replica transition state: prospect of quantum entanglement at homodromic Bjerrum defect site. J Mol Model 2023; 29:242. [PMID: 37436555 PMCID: PMC10338397 DOI: 10.1007/s00894-023-05646-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 07/01/2023] [Indexed: 07/13/2023]
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.
Collapse
Affiliation(s)
- Sanyasi Sitha
- Department of Chemical Sciences, APK Campus, University of Johannesburg, PO Box 524, Auckland Park, Johannesburg, 2006, South Africa.
| |
Collapse
|
2
|
Moore B, Mahoney K, Zeng MF, Djuricanin P, Momose T. Ultraviolet Photodissociation of Proteinogenic Amino Acids. J Am Chem Soc 2023; 145:11045-11055. [PMID: 37167534 DOI: 10.1021/jacs.3c00124] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The ultraviolet photochemistry of the amino acids glycine, leucine, proline, and serine in their neutral forms was investigated using parahydrogen matrix-isolation spectroscopy. Irradiation by 213 nm light destroys the chirality of all three chiral amino acids as a result of the α-carbonyl C-C bond cleavage and hydrocarboxyl (HOCO) radical production. The temporal behavior of the Fourier-transform infrared spectra revealed that HOCO radicals rapidly reach a steady state, which occurs predominantly due to photodissociation of HOCO into CO + OH or CO2 + H. In glycine and leucine, the amine radicals generated by the α-carbonyl C-C bond cleavage rapidly undergo hydrogen elimination to yield methanimine and 3-methylbutane-1-imine, respectively. Breaking of the α-carbonyl C-C bond in proline appeared to yield 1-pyrroline, although due to its weak absorption it remains unconfirmed. In serine, additional products were formaldehyde and E/Z ethanimine. The present study shows that the direct production of HOCO previously observed in α-alanine generalizes to other amino acids of varying structure. It also revealed a tendency for amino acid photolysis to form imines rather than amine radicals. HOCO should be useful in the search for amino acids in interstellar space, particularly in combination with simple imine molecules.
Collapse
Affiliation(s)
- Brendan Moore
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Kyle Mahoney
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Mei Fei Zeng
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Pavle Djuricanin
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Takamasa Momose
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| |
Collapse
|
3
|
Muddasser I, Nguyen AHM, Strom AI, Hardee AM, Pluid BG, Anderson DT. Infrared Spectroscopic Studies of Oxygen Atom Quantum Diffusion in Solid Parahydrogen. J Phys Chem A 2023; 127:2751-2764. [PMID: 36930520 DOI: 10.1021/acs.jpca.3c00266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
The thermally induced diffusion of atomic species in noble gas matrices was studied extensively in the 1990s to investigate low-temperature solid-state reactions and to synthesize reactive intermediates. In contrast, much less is known about the diffusion of atomic species in quantum solids such as solid parahydrogen (p-H2). While hydrogen atoms were shown to diffuse in normal-hydrogen solids at 4.2 K as early as 1989, the diffusion of other atomic species in solid p-H2 has not been reported in the literature. The in situ photogeneration of atomic oxygen, by ArF laser irradiation of an O2-doped p-H2 solid at 193 nm, is studied here to investigate the diffusion of O(3P) atoms in a quantum solid. The O(3P) atom mobility is detected by measuring the kinetics of the O(3P) + O2 → O3 reaction after photolysis via infrared spectroscopy of the O3 reaction product. This reaction is barrierless and is thus assumed to be diffusion-controlled under these conditions such that the reaction rate constant can be used to estimate the oxygen atom diffusion coefficient. The O3 growth curves are well fit by single exponential expressions allowing the pseudo-first-order rate constant for the O(3P) + O2 → O3 reaction to be extracted. The reaction rates are affected strongly by the p-H2 crystal morphology and display a non-Arrhenius-type temperature dependence consistent with quantum diffusion of the O(3P) atom. The experimental results are compared to H(2S) atom reaction studies in p-H2, analogous studies in noble gas matrices, and laboratory studies of atomic diffusion in astronomical ices and surfaces.
Collapse
Affiliation(s)
- Ibrahim Muddasser
- Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071, United States
| | - Anh H M Nguyen
- Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071, United States
| | - Aaron I Strom
- Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071, United States
| | - Aaron M Hardee
- Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071, United States
| | - Bryan G Pluid
- Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071, United States
| | - David T Anderson
- Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071, United States
| |
Collapse
|
4
|
Lin SY, Huang WJ, Chou SL, Chen HF, Wu YJ. Formation of Para-H 2O by Vacuum-UV Photolysis of O 2 in Solid Hydrogen: Implication for Astrochemistry. J Phys Chem Lett 2022; 13:10439-10446. [PMID: 36326470 DOI: 10.1021/acs.jpclett.2c02665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The observation that the ortho to para ratio (OPR) of interstellar H2O is smaller than 3 is an important yet unresolved subject in astronomy. We irradiated O2 embedded in solid H2 at 3 K with vacuum-ultraviolet (VUV) light and observed IR lines associated with para-H2O (denoted as pH2O) and nonrotating H2O-(oH2)n (where oH2 denotes ortho-H2) but no lines associated with ortho-H2O (denoted as oH2O). After maintaining the matrix in darkness for ∼30 h, the amount of pH2O decreased, accompanied by an increase in H2O-(oH2)n via diffusion of oH2. After that, the continuous nuclear-spin conversion from oH2 to para-H2 (denoted as pH2) in solid H2 over time resulted in the conversion of nonrotating H2O-(oH2)n to rotating pH2O in solid pH2. The observation of the formation and conversion of pH2O in our experiment suggests a plausible route in which VUV irradiation of O2 and H2 adsorbed on grain surfaces might be responsible for the smaller OPR of interstellar H2O.
Collapse
Affiliation(s)
- Shu-Yu Lin
- Department of Applied Chemistry and Institute of Molecular Science, National Yang Ming Chiao Tung University, Hsinchu300093, Taiwan
| | - Wen-Jian Huang
- National Synchrotron Radiation Research Center, Hsinchu30076, Taiwan
| | - Sheng-Lung Chou
- National Synchrotron Radiation Research Center, Hsinchu30076, Taiwan
| | - Hui-Fen Chen
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, 100 Shih-Chuan First Road, Kaohsiung80708, Taiwan
| | - Yu-Jong Wu
- Department of Applied Chemistry and Institute of Molecular Science, National Yang Ming Chiao Tung University, Hsinchu300093, Taiwan
- National Synchrotron Radiation Research Center, Hsinchu30076, Taiwan
| |
Collapse
|
5
|
Moore B, Toh SY, Wong YTA, Bashiri T, McKinnon A, Wai Y, Alethea Lee KW, Ovchinnikov P, Chiang CY, Djuricanin P, Momose T. Hydrocarboxyl Radical as a Product of α-Alanine Ultraviolet Photolysis. J Phys Chem Lett 2021; 12:11992-11997. [PMID: 34889613 DOI: 10.1021/acs.jpclett.1c03104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
UV photodissociation of α-alanine was studied by parahydrogen matrix isolation infrared spectroscopy. The temporal behavior of Fourier transform infrared spectra revealed that UV irradiation at 213 nm yielded the HOCO radical as a direct photoproduct from the S2 excited state. The concentration of HOCO quickly approached a steady state due to secondary photodissociation of HOCO to produce CO2 + H or CO + OH. On the other hand, no photoproducts were detected by S1 excitation at 266 nm. Irradiation of fully deuterated α-alanine at 213 nm yielded ∼2 times more cis-DOCO radicals than the lower energy isomer trans-DOCO, indicating that the conformation of the hydroxyl group is fairly well-preserved upon photodissociation of α-alanine. The present study suggests that HOCO may be a good tracer species in the search for amino acids in interstellar space.
Collapse
Affiliation(s)
- Brendan Moore
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
| | - Shin Yi Toh
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
| | - Y T Angel Wong
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
| | - Termeh Bashiri
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
| | - Alexandra McKinnon
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
| | - Yonnie Wai
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
| | - Ka Wing Alethea Lee
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
| | - Polina Ovchinnikov
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
| | - Chih-Yu Chiang
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
| | - Pavle Djuricanin
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
| | - Takamasa Momose
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
| |
Collapse
|