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McNamara L, Waldron A, Thomas M, Jones W, O'Rourke P, Darrell S, Strange Fessler KA. Investigating the hydrolysis of cryogenically layered molybdenum hexafluoride through a disordered hydrogen-bonded network. Phys Chem Chem Phys 2023; 25:2990-2998. [PMID: 36606495 DOI: 10.1039/d2cp04147b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Molybdenum hexafluoride (MoF6) is used as a non-radioactive substitute for uranium to study the hydrolysis of metal hexafluorides. Molybdenum hexafluoride gas and water vapor, from the air, were sequentially layered onto a diamond substrate kept at liquid nitrogen temperature using a custom designed cryogenic cell with a copper cold finger. Reaction progress was monitored by transmission Fourier Transform Infrared Spectroscopy (FTIR) through the layers and diamond substrate over several hours while allowing the substrate to warm. Changes in the modes in the 500-1000 cm-1 region are tracked as the reaction progresses in order to identify intermediate species. Strong absorption features are also observed in the 1000-3000 cm-1 range, suggesting the presence of ionic dissociation intermediates trapped in a disordered H-bonded network of cryogenic hydrofluoric acid. A possible reaction pathway is proposed and the final hydrolysis product is characterized by FTIR, UV-vis, and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS).
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Affiliation(s)
- Louis McNamara
- Savannah River National Laboratory, 301 Gateway Drive, Aiken, 29803, SC, USA.
| | - Abigail Waldron
- Savannah River National Laboratory, 301 Gateway Drive, Aiken, 29803, SC, USA.
| | - Michael Thomas
- Savannah River National Laboratory, 301 Gateway Drive, Aiken, 29803, SC, USA.
| | - Willis Jones
- Savannah River National Laboratory, 301 Gateway Drive, Aiken, 29803, SC, USA. .,University of North Florida, 1 UNF Drive, Jacksonville, FL, 32224, USA
| | - Patrick O'Rourke
- Savannah River National Laboratory, 301 Gateway Drive, Aiken, 29803, SC, USA.
| | - Simmons Darrell
- Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, 37830, TN, USA
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Abstract
Excess protons play a key role in the chemical reactions of ice because of their exceptional mobility, even when the diffusion of atoms and molecules is suppressed in ice at low temperatures. This article reviews the current state of knowledge on the properties of excess protons in ice, with a focus on the involvement of protons in chemical reactions. The mechanism of efficient proton transport in ice, which involves a proton-hopping relay along the hydrogen-bond ice network and the reorientation of water, is discussed and compared with the inefficient transport of hydroxide in ice. Distinctly different properties of protons residing in the ice interior and on the ice surface are emphasized. Recent observations of the spontaneous occurrence of reactions in ice at low temperatures, which include the dissociation of protic acids and the hydrolysis of acidic oxides, are discussed with regard to the kinetic and thermodynamic effects of mobile protons on the promotion of unique chemical processes of ice.
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Affiliation(s)
- Du Hyeong Lee
- Korea Polar Research Institute, 26 Songdomirae-ro, Incheon 21990, South Korea
| | - Heon Kang
- Department of Chemistry and The Research Institute of Basic Sciences, Seoul National University, 1 Gwanak-ro, Seoul 08826, South Korea
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Maurais J, Ayotte P. Tailoring electric field standing waves in reflection-absorption infrared spectroscopy to enhance absorbance from adsorbates on ice surfaces. J Chem Phys 2020; 152:074202. [PMID: 32087646 DOI: 10.1063/1.5141934] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The spectroscopic detection of molecules adsorbed onto ice surfaces at coverages similar to those encountered under typical environmental conditions requires high surface selectivity and sensitivity that few techniques can afford. An experimental methodology allowing a significant enhancement in the absorbance from adsorbed molecules is demonstrated herein. It exploits Electric Field Standing Wave (EFSW) effects intrinsic to grazing incidence Reflection-Absorption Infrared (RAIR) spectroscopy, where film thickness dependent optical interferences occur between the multiple reflections of the IR beam at the film-vacuum and the substrate-film interfaces. In this case study, CH4 is used as a probe molecule and is deposited on a 20 ML coverage dense amorphous solid water film adsorbed onto solid Ar underlayers of various thicknesses. We observe that, at thicknesses where destructive interferences coincide with the absorption features from the CH stretching and HCH bending vibrational modes of methane, their intensity increases by a factor ranging from 10 to 25. Simulations of the RAIR spectra of the composite stratified films using a classical optics model reproduce the Ar underlayer coverage dependent enhancements of the absorbance features from CH4 adsorbed onto the ice surface. They also reveal that the enhancements occur when the square modulus of the total electric field at the film's surface reaches its minimum value. Exploiting the EFSW effect allows the limit of detection to be reduced to a coverage of (0.2 ± 0.2) ML CH4, which opens up interesting perspectives for spectroscopic studies of heterogeneous atmospheric chemistry at coverages that are more representative of those found in the natural environment.
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Affiliation(s)
- Josée Maurais
- Département de Chimie, Université de Sherbrooke, 2500 Boulevard de l'Université, Sherbrooke, Québec J1K 2R1, Canada
| | - Patrick Ayotte
- Département de Chimie, Université de Sherbrooke, 2500 Boulevard de l'Université, Sherbrooke, Québec J1K 2R1, Canada
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Park Y, Shin S, Kang H. Entropy-Driven Spontaneous Reaction in Cryogenic Ice: Dissociation of Fluoroacetic Acids. J Phys Chem Lett 2018; 9:4282-4286. [PMID: 30001139 DOI: 10.1021/acs.jpclett.8b01825] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Chemical reactions are extremely difficult to occur in ice at low temperature, where atoms and molecules are frozen in position with minimal thermal energy and entropy. Contrary to this general behavior, certain weak acids including fluoroacetic acids dissociate spontaneously and more efficiently in cryogenic ice than in aqueous solution at room temperaure. The enhanced reactivity of weak acids is an unexpected consequence of proton-transfer equilibrium in ice. The configurational entropy of protons in ice shifts the acid dissociation equilibrium forward. This configurational entropy, although a solid-state property, is comparatively large in magnitude with the entropy of vaporization and can effectively drive proton-transfer reactions in ice.
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Affiliation(s)
- Youngwook Park
- Department of Chemistry , Seoul National University , 1 Gwanak-ro , Seoul 08826 , Republic of Korea
| | - Sunghwan Shin
- Department of Chemistry , Seoul National University , 1 Gwanak-ro , Seoul 08826 , Republic of Korea
| | - Heon Kang
- Department of Chemistry , Seoul National University , 1 Gwanak-ro , Seoul 08826 , Republic of Korea
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Synthesis and study of tetramethylammonium hexafluoridozirconate and hexafluoridohafnate solvated by H2O·HF adducts and [N(CH3)4]2ZrF6. J Fluor Chem 2013. [DOI: 10.1016/j.jfluchem.2013.01.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Marchand P, Marcotte G, Ayotte P. Spectroscopic Study of HNO3 Dissociation on Ice. J Phys Chem A 2012; 116:12112-22. [DOI: 10.1021/jp309533f] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Patrick Marchand
- Département de Chimie, Université de Sherbrooke, 2500, boulevard université, Sherbrooke,
Québec J1K 2R1, Canada
| | - Guillaume Marcotte
- Département de Chimie, Université de Sherbrooke, 2500, boulevard université, Sherbrooke,
Québec J1K 2R1, Canada
| | - Patrick Ayotte
- Département de Chimie, Université de Sherbrooke, 2500, boulevard université, Sherbrooke,
Québec J1K 2R1, Canada
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Ayotte P, Marchand P, Daschbach JL, Smith RS, Kay BD. HCl Adsorption and Ionization on Amorphous and Crystalline H2O Films below 50 K. J Phys Chem A 2011; 115:6002-14. [DOI: 10.1021/jp110398j] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Patrick Ayotte
- Département de Chimie, Université de Sherbrooke, 2500 Boulevard Université, Sherbrooke, Québec, Canada J1K 2R1
| | - Patrick Marchand
- Département de Chimie, Université de Sherbrooke, 2500 Boulevard Université, Sherbrooke, Québec, Canada J1K 2R1
| | - John L. Daschbach
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Mail Stop K8-88, Richland, Washington 99352, United States
| | - R. Scott Smith
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Mail Stop K8-88, Richland, Washington 99352, United States
| | - Bruce D. Kay
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Mail Stop K8-88, Richland, Washington 99352, United States
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Marcotte G, Ayotte P. Strong intermolecular coupling between the HF stretching and H2O bending vibrations in HF:H2O binary amorphous solids: breakdown of the electrostatic description of the hydrogen bond. J Chem Phys 2011; 134:114522. [PMID: 21428647 DOI: 10.1063/1.3562368] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The coupling mechanism between the HF stretching and H(2)O bending vibrations observed in the infrared spectra of HF:H(2)O binary amorphous solids is analyzed using a simple cluster model. The intermolecular vibrational coupling derived from electrostatic potentials is one order of magnitude smaller, and of the opposite sign, than that obtained from electronic structure-based potentials. This highlights the distinctively covalent character of strong H-bonds and unveils fundamental weaknesses of electrostatic descriptions of vibrational energy transfer in liquid water and aqueous solutions.
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Affiliation(s)
- Guillaume Marcotte
- Département de chimie, Université de Sherbrooke, 2500 boulevard université, Sherbrooke, Québec J1K 2R1, Canada.
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Joutsuka T, Ando K. Dynamics of Proton Transfer and Vibrational Relaxation in Dilute Hydrofluoric Acid. J Phys Chem A 2011; 115:678-84. [DOI: 10.1021/jp108413p] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tatsuya Joutsuka
- Department of Chemistry, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Koji Ando
- Department of Chemistry, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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Abstract
We have performed the multistate empirical valence bond (MS-EVB) molecular dynamics simulations of a dilute hydrofluoric acid solution at ambient temperature to study the hydration structure associated with its weak acidity. The developed MS-EVB model showed reasonable agreement with experimental and previous ab initio molecular dynamics and reference interaction site model self-consistent field simulations for the free energy and structural properties. The local tetrahedral and translational order parameters around the fluorine atom significantly increase in the transition and product states of the HF dissociation reaction. This indicates that the angular and translational rearrangements of the hydrogen-bond topology are necessary especially around the fluorine atom. At the transition state of the proton transfer, the tetrahedral order parameters are very large, whereas the translational order parameters are not. This suggests that for the proton transfer to occur the large angular rearrangements of the hydrogen-bond topology are more necessary than the translational ones.
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Affiliation(s)
- Tatsuya Joutsuka
- Department of Chemistry, Kyoto University, Sakyo-ku, Kyoto, Japan.
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11
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Buin A, Iftimie R. Molecular polarizabilities in aqueous proton transfer reactions. J Chem Phys 2009; 131:234507. [DOI: 10.1063/1.3275963] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Ayotte P, Rafiei Z, Porzio F, Marchand P. Dissociative adsorption of hydrogen fluoride onto amorphous solid water. J Chem Phys 2009; 131:124517. [DOI: 10.1063/1.3231999] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Thomas V, Iftimie R. Toward Understanding the Dissociation of Weak Acids in Water: 1. Using IR Spectroscopy to Identify Proton-Shared Hydrogen-Bonded Ion-Pair Intermediates. J Phys Chem B 2008; 113:4152-60. [DOI: 10.1021/jp807378x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Vibin Thomas
- Département de Chimie, Université de Montréal, CP 6128, succursale Centre-Ville, Montréal, H3C3J7, Canada
| | - Radu Iftimie
- Département de Chimie, Université de Montréal, CP 6128, succursale Centre-Ville, Montréal, H3C3J7, Canada
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Cholette F, Zubkov T, Smith RS, Dohnálek Z, Kay BD, Ayotte P. Infrared Spectroscopy and Optical Constants of Porous Amorphous Solid Water. J Phys Chem B 2008; 113:4131-40. [DOI: 10.1021/jp806738a] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- François Cholette
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Mail Stop K8-88, Richland, Washington 99352, and Département de chimie, Université de Sherbrooke, 2500 Boulevard Université, Sherbrooke, Québec, Canada J1K 2R1
| | - Tykhon Zubkov
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Mail Stop K8-88, Richland, Washington 99352, and Département de chimie, Université de Sherbrooke, 2500 Boulevard Université, Sherbrooke, Québec, Canada J1K 2R1
| | - R. Scott Smith
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Mail Stop K8-88, Richland, Washington 99352, and Département de chimie, Université de Sherbrooke, 2500 Boulevard Université, Sherbrooke, Québec, Canada J1K 2R1
| | - Zdenek Dohnálek
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Mail Stop K8-88, Richland, Washington 99352, and Département de chimie, Université de Sherbrooke, 2500 Boulevard Université, Sherbrooke, Québec, Canada J1K 2R1
| | - Bruce D. Kay
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Mail Stop K8-88, Richland, Washington 99352, and Département de chimie, Université de Sherbrooke, 2500 Boulevard Université, Sherbrooke, Québec, Canada J1K 2R1
| | - Patrick Ayotte
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Mail Stop K8-88, Richland, Washington 99352, and Département de chimie, Université de Sherbrooke, 2500 Boulevard Université, Sherbrooke, Québec, Canada J1K 2R1
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