1
|
Roszak K, Maciejewski A, Katrusiak A, Krystkowiak E. Solute - solvent repulsion effects on the absorption spectra of anthracene in n-hexane investigated under high pressure. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 299:122822. [PMID: 37182252 DOI: 10.1016/j.saa.2023.122822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 04/14/2023] [Accepted: 05/03/2023] [Indexed: 05/16/2023]
Abstract
The band positions in the UV-VIS absorption spectra of compressed solution of anthracene in n-hexane significantly depend not only on the dispersive but also on the repulsive solute-solvent interactions, what has so far been omitted. Their strength is determined not only by the solvent polarity but also by Onsager cavity radius changing with pressure. The results obtained for anthracene show that repulsive interactions should be included in the interpretation of barochromic and solvatochromic results of aromatic compounds. We show that the barochromic studies in the liquid solvent can be an alternative to solvatochromic studies, e.g. to determine the polarizability of organic molecules in the electronic excited state. The pressure-induced polarity change in n-hexane exceeds that induced by the exchange of n-alkane solvents between n-pentane and n-hexadecane.
Collapse
Affiliation(s)
- Kinga Roszak
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614 Poznań, Poland
| | - Andrzej Maciejewski
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614 Poznań, Poland
| | - Andrzej Katrusiak
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614 Poznań, Poland
| | - Ewa Krystkowiak
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614 Poznań, Poland.
| |
Collapse
|
2
|
Cammi R, Chen B. Studying and exploring potential energy surfaces of compressed molecules: a fresh theory from the eXtreme Pressure Polarizable Continuum Model. J Chem Phys 2022; 157:114101. [DOI: 10.1063/5.0104269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We present a new theory for studying and exploring the potential energy surface of compressed molecular systems as described within the XP-PCM framework. The effective potential energy surface is defined by the sum of the electronic energy of the compressed system and the pressure-volume work that is necessary in order to create the compression cavity at the given condition of pressure. We show that the resulting total energy Gt is related to the electronic energy by a Legendre transform, in which the pressure and volume of the compression cavity are the conjugate variables. We present an analytical expression for the evaluation of the gradient of the total energy ∇Gt to be used for the geometry optimization of equilibrium geometries and transition states of compressed molecular systems. We also show that, as a result of the Legendre transform property, the potential energy surface can be studied explicitly as function of the pressure, leading to an explicit connection with the well-known Hammond postulate. As a proof of concept, we present the application of the theory to studying and determining of the optimized geometry of compressed methane and the transition state of electrocyclic ring-closure of hexatriene and of H-transfer between two methyl radicals.
Collapse
Affiliation(s)
- Roberto Cammi
- Dipartimento di Scienze Chimica della Vita e della Sostenibilità Ambientale, Università degli Studi di Parma, Italy
| | - Bo Chen
- Donostia international physics center, Spain
| |
Collapse
|
3
|
Sessa F, Rahm M. Electronegativity Equilibration. J Phys Chem A 2022; 126:5472-5482. [PMID: 35939052 PMCID: PMC9393861 DOI: 10.1021/acs.jpca.2c03814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Controlling the distribution of electrons in materials
is the holy
grail of chemistry and material science. Practical attempts at this
feat are common but are often reliant on simplistic arguments based
on electronegativity. One challenge is knowing when such arguments
work, and which other factors may play a role. Ultimately, electrons
move to equalize chemical potentials. In this work, we outline a theory
in which chemical potentials of atoms and molecules are expressed
in terms of reinterpretations of common chemical concepts and some
physical quantities: electronegativity, chemical hardness, and the
sensitivity of electronic repulsion and core levels with respect to
changes in the electron density. At the zero-temperature limit, an
expression of the Fermi level emerges that helps to connect several
of these quantities to a plethora of material properties, theories
and phenomena predominantly explored in condensed matter physics.
Our theory runs counter to Sanderson’s postulate of electronegativity
equalization and allows a perspective in which electronegativities
of bonded atoms need not be equal. As chemical potentials equalize
in this framework, electronegativities equilibrate.
Collapse
Affiliation(s)
- Francesco Sessa
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| | - Martin Rahm
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| |
Collapse
|
4
|
Rahm M. Electronegativity at the Shock Front. PROPELLANTS EXPLOSIVES PYROTECHNICS 2022. [DOI: 10.1002/prep.202100306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Martin Rahm
- Department of Chemistry and Chemical Engineering Chalmers University of Technology Kemigården 4 SE-412 96 Gothenburg Sweden
| |
Collapse
|
5
|
An Observation Related to the Pressure Dependence of Ionic Radii. GEOSCIENCES 2022. [DOI: 10.3390/geosciences12060246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Here it is shown that the crystal radii of ions are represented by a simple relation rcryst = rB3√(10 m)/N, where m and N are small integer numbers determined by the principal and orbital quantum numbers and valence, and rB is the Bohr radius. The relation holds to within 5%. This finding elucidates that despite their original definition crystal- and ionic radii are not classical but represent the limiting case of spherically symmetric spatial averages of the valence electron states and, therefore, are able to reflect changes in the valence electron configuration with pressure and temperature. The relation is used to show general pressure-effects on the radii, in particular the increase of bond coordination with pressure and metallization as limiting state. The pressure-effect is exemplified for the elements Mg and Si as major constituent cations in the Earth’s mantle, and for Ba as a large ionic lithophile element. It is found that at least to about 140 GPa the radii depend linearly on pressure. Further, if a generalization is permitted for just three elements, the pressure-dependence is lesser the higher the charge of the ion. The three elements exhibit a much weaker pressure-dependence than previously calculated non-bonding radii. For mantle geochemistry this finding implies that elements incompatible in the upper mantle remain so for the main lower mantle minerals bridgmanite and periclase and are hosted by davemaoite.
Collapse
|
6
|
Sentell Z, Spooner J, Weinberg N. Molecular Dynamics Calculations of Partial Molar Volumes of Amino Acids in Aqueous Solutions. CAN J CHEM 2022. [DOI: 10.1139/cjc-2021-0217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Partial molar volumes of amino acids in their zwitterionic and molecular forms have been calculated using molecular dynamics simulations of these systems in aqueous solutions. Calculations performed with the TIP4P, SPC (rigid and flexible), SPC/E, and polarizable water models show that the choice of water model can have a significant impact on the calculated volumes. The effect of treatment of long-range electrostatic interactions on the calculated results was also investigated. Volumes obtained in simulations with a properly chosen water model fit well the experimental data for both molecular and zwitterionic forms of amino acids.
Collapse
Affiliation(s)
- Zachary Sentell
- University of the Fraser Valley, 1011, Department of Chemistry, Abbotsford, Canada
| | - Jacob Spooner
- University of the Fraser Valley, 1011, Department of Chemistry, Abbotsford, Canada, V2S 7M8
| | - Noham Weinberg
- University of the Fraser Valley, 1011, Department of Chemistry, Abbotsford, Canada, V2S 7M8
| |
Collapse
|
7
|
Lin J, Yang Q, Li X, Zhang X, Li F, Yang G. Pressure-stabilized hexafluorides of first-row transition metals. Phys Chem Chem Phys 2022; 24:1736-1742. [PMID: 34985073 DOI: 10.1039/d1cp04446j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fluorine chemistry was demonstrated to show the importance of stretching the limits of chemical synthesis, oxidation state, and chemical bonding at ambient conditions. Thus far, the highest fluorine stoichiometry of a neutral first-row transition-metal fluoride is five, in VF5 and CrF5. Pressure can stabilize new stoichiometric compounds that are inaccessible at ambient conditions. Here, we attempted to delineate the fluorination limits of first-row transition metals at a high pressure through first-principles swarm-intelligence structure searching simulations. Besides reproducing the known compounds, our extensive search has resulted in a plethora of unreported compounds: CrF6, MnF6, FeF4, FeF5, FeF6, and CoF4, indicating that the application of pressure achieves not only the fluorination limit (e.g., hexafluoride) but also the long-sought bulky tetrafluorides. Our current results provide a significant step forward towards a comprehensive understanding of the fluorination limit of first-row transition metals.
Collapse
Affiliation(s)
- Jianyan Lin
- State Key Laboratory of Metastable Materials Science & Technology and Key Laboratory for Microstructural Material Physics of Hebei Province, School of Science, Yanshan University, Qinhuangdao 066004, China. .,College of Physics, Changchun Normal University, Changchun 130032, China
| | - Qiuping Yang
- State Key Laboratory of Metastable Materials Science & Technology and Key Laboratory for Microstructural Material Physics of Hebei Province, School of Science, Yanshan University, Qinhuangdao 066004, China. .,Centre for Advanced Optoelectronic Functional Materials Research and Key Laboratory for UV Light-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, China
| | - Xing Li
- State Key Laboratory of Metastable Materials Science & Technology and Key Laboratory for Microstructural Material Physics of Hebei Province, School of Science, Yanshan University, Qinhuangdao 066004, China.
| | - Xiaohua Zhang
- State Key Laboratory of Metastable Materials Science & Technology and Key Laboratory for Microstructural Material Physics of Hebei Province, School of Science, Yanshan University, Qinhuangdao 066004, China. .,Centre for Advanced Optoelectronic Functional Materials Research and Key Laboratory for UV Light-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, China
| | - Fei Li
- State Key Laboratory of Metastable Materials Science & Technology and Key Laboratory for Microstructural Material Physics of Hebei Province, School of Science, Yanshan University, Qinhuangdao 066004, China.
| | - Guochun Yang
- State Key Laboratory of Metastable Materials Science & Technology and Key Laboratory for Microstructural Material Physics of Hebei Province, School of Science, Yanshan University, Qinhuangdao 066004, China. .,Centre for Advanced Optoelectronic Functional Materials Research and Key Laboratory for UV Light-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, Changchun 130024, China
| |
Collapse
|
8
|
Mroz AM, Davenport AM, Sterling J, Davis J, Hendon CH. An Electric Field–Based Approach for Quantifying Effective Volumes and Radii of Chemically Affected Space. Chem Sci 2022; 13:6558-6566. [PMID: 35756514 PMCID: PMC9172366 DOI: 10.1039/d2sc00780k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 04/29/2022] [Indexed: 11/21/2022] Open
Abstract
Chemical shape and size play a critical role in chemistry. The van der Waals (vdW) radius, a familiar manifold used to quantify size by assuming overlapping spheres, provides rapid estimates of size in atoms, molecules, and materials. However, the vdW method may be too rigid to describe highly polarized systems and chemical species that stray from spherical atomistic environments. To deal with these exotic chemistries, numerous alternate methods based on electron density have been presented. While each boasts inherent generality, all define the size of a chemical system, in one way or another, by its electron density. Herein, we revisit the longstanding problem of assessing sizes of atoms and molecules, instead through examination of the local electric field produced by them. While conceptually different than nuclei-centered methods like that of van der Waals, the field assesses chemically affected volumes. This approach implicitly accounts for long-range fields in highly polar systems and predicts that cations should affect more space than neutral counterparts. Computing atomic and molecular volumes from DFT and ab initio-based electric fields.![]()
Collapse
Affiliation(s)
- Austin M Mroz
- Department of Chemistry and Biochemistry, University of Oregon Eugene OR 97403 USA
| | - Audrey M Davenport
- Department of Chemistry and Biochemistry, University of Oregon Eugene OR 97403 USA
| | - Jasper Sterling
- Department of Chemistry and Biochemistry, University of Oregon Eugene OR 97403 USA
| | - Joshua Davis
- Department of Chemistry and Biochemistry, University of Oregon Eugene OR 97403 USA
| | - Christopher H Hendon
- Department of Chemistry and Biochemistry, University of Oregon Eugene OR 97403 USA
| |
Collapse
|
9
|
Eeckhoudt J, Bettens T, Geerlings P, Cammi R, Chen B, Alonso M, De Proft F. Conceptual Density Functional Theory under Pressure: Part I. XP-PCM Method Applied to Atoms. Chem Sci 2022; 13:9329-9350. [PMID: 36093025 PMCID: PMC9384819 DOI: 10.1039/d2sc00641c] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 07/14/2022] [Indexed: 11/21/2022] Open
Abstract
High pressure chemistry offers the chemical community a range of possibilities to control chemical reactivity, develop new materials and fine-tune chemical properties. Despite the large changes that extreme pressure brings to the table, the field has mainly been restricted to the effects of volume changes and thermodynamics with less attention devoted to electronic effects at the molecular scale. This paper combines the conceptual DFT framework for analyzing chemical reactivity with the XP-PCM method for simulating pressures in the GPa range. Starting from the new derivatives of the energy with respect to external pressure, an electronic atomic volume and an atomic compressibility are found, comparable to their enthalpy analogues, respectively. The corresponding radii correlate well with major known sets of this quantity. The ionization potential and electron affinity are both found to decrease with pressure using two different methods. For the electronegativity and chemical hardness, a decreasing and increasing trend is obtained, respectively, and an electronic volume-based argument is proposed to rationalize the observed periodic trends. The cube of the softness is found to correlate well with the polarizability, both decreasing under pressure, while the interpretation of the electrophilicity becomes ambiguous at extreme pressures. Regarding the electron density, the radial distribution function shows a clear concentration of the electron density towards the inner region of the atom and periodic trends can be found in the density using the Carbó quantum similarity index and the Kullback–Leibler information deficiency. Overall, the extension of the CDFT framework with pressure yields clear periodic patterns. Conceptual DFT has provided a framework in which to study chemical reactivity. Since high pressure is more and more a tool to control reactions and fine-tune chemical properties, this variable is introduced into the CDFT framework.![]()
Collapse
Affiliation(s)
- J Eeckhoudt
- General Chemistry Department (ALGC), Vrije Universiteit Brussel (VUB) Brussels Belgium
| | - T Bettens
- General Chemistry Department (ALGC), Vrije Universiteit Brussel (VUB) Brussels Belgium
| | - P Geerlings
- General Chemistry Department (ALGC), Vrije Universiteit Brussel (VUB) Brussels Belgium
| | - R Cammi
- Department of Chemical Science, Life Science and Environmental Sustainability, University of Parma Parma Italy
| | - B Chen
- Donostia International Physics Center Donostia-San Sebastian Spain
- IKERBASQUE, Basque Foundation for Science Plaza Euskadi 5 48009 Bilbao Spain
| | - M Alonso
- General Chemistry Department (ALGC), Vrije Universiteit Brussel (VUB) Brussels Belgium
| | - F De Proft
- General Chemistry Department (ALGC), Vrije Universiteit Brussel (VUB) Brussels Belgium
| |
Collapse
|
10
|
Boccalini M, Cammi R, Pagliai M, Cardini G, Schettino V. Toward an Understanding of the Pressure Effect on the Intramolecular Vibrational Frequencies of Sulfur Hexafluoride. J Phys Chem A 2021; 125:6362-6373. [PMID: 34263605 PMCID: PMC8389992 DOI: 10.1021/acs.jpca.1c02595] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The structural and vibrational properties of the molecular units of sulfur hexafluoride crystal as a function of pressure have been studied by the Extreme Pressure Polarizable Continuum Model (XP-PCM) method. Within the XP-PCM model, single molecule calculations allow a consistent interpretation of the experimental measurements when considering the effect of pressure on both the molecular structure and the vibrational normal modes. This peculiar aspect of XP-PCM provides a detailed description of the electronic origin of normal modes variations with pressure, via the curvature of the potential energy surface and via the anharmonicity of the normal modes. When applied to the vibrational properties of the sulfur hexafluoride crystal, the XP-PCM method reveals a hitherto unknown interpretation of the effects of the pressure on the vibrational normal modes of the molecular units of this crystal.
Collapse
Affiliation(s)
- Matteo Boccalini
- Dipartimento di Chimica "Ugo Schiff", Università degli Studi di Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy
| | - Roberto Cammi
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Universitá degli Studi di Parma, Parco Area delle Scienze 11/a, 43124 Parma, Italy
| | - Marco Pagliai
- Dipartimento di Chimica "Ugo Schiff", Università degli Studi di Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy
| | - Gianni Cardini
- Dipartimento di Chimica "Ugo Schiff", Università degli Studi di Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy
| | - Vincenzo Schettino
- Dipartimento di Chimica "Ugo Schiff", Università degli Studi di Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy
| |
Collapse
|
11
|
Gale A, Hruska E, Liu F. Quantum chemistry for molecules at extreme pressure on graphical processing units: Implementation of extreme-pressure polarizable continuum model. J Chem Phys 2021; 154:244103. [PMID: 34241353 DOI: 10.1063/5.0056480] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Pressure plays essential roles in chemistry by altering structures and controlling chemical reactions. The extreme-pressure polarizable continuum model (XP-PCM) is an emerging method with an efficient quantum mechanical description of small- and medium-sized molecules at high pressure (on the order of GPa). However, its application to large molecular systems was previously hampered by a CPU computation bottleneck: the Pauli repulsion potential unique to XP-PCM requires the evaluation of a large number of electric field integrals, resulting in significant computational overhead compared to the gas-phase or standard-pressure polarizable continuum model calculations. Here, we exploit advances in graphical processing units (GPUs) to accelerate the XP-PCM-integral evaluations. This enables high-pressure quantum chemistry simulation of proteins that used to be computationally intractable. We benchmarked the performance using 18 small proteins in aqueous solutions. Using a single GPU, our method evaluates the XP-PCM free energy of a protein with over 500 atoms and 4000 basis functions within half an hour. The time taken by the XP-PCM-integral evaluation is typically 1% of the time taken for a gas-phase density functional theory (DFT) on the same system. The overall XP-PCM calculations require less computational effort than that for their gas-phase counterpart due to the improved convergence of self-consistent field iterations. Therefore, the description of the high-pressure effects with our GPU-accelerated XP-PCM is feasible for any molecule tractable for gas-phase DFT calculation. We have also validated the accuracy of our method on small molecules whose properties under high pressure are known from experiments or previous theoretical studies.
Collapse
Affiliation(s)
- Ariel Gale
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA
| | - Eugen Hruska
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA
| | - Fang Liu
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA
| |
Collapse
|
12
|
Rahm M, Erhart P, Cammi R. Relating atomic energy, radius and electronegativity through compression. Chem Sci 2021; 12:2397-2403. [PMID: 34164004 PMCID: PMC8179346 DOI: 10.1039/d0sc06675c] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Trends in atomic properties are well-established tools for guiding the analysis and discovery of materials. Here, we show how compression can reveal a long sought-after connection between two central chemical concepts - van-der-Waals (vdW) radii and electronegativity - and how these relate to the driving forces behind chemical and physical transformations.
Collapse
Affiliation(s)
- Martin Rahm
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology SE-412 96 Gothenburg Sweden
| | - Paul Erhart
- Department of Physics, Chalmers University of Technology SE-412 96 Gothenburg Sweden
| | - Roberto Cammi
- Department of Chemical Science, Life Science and Environmental Sustainability, University of Parma Parma Italy
| |
Collapse
|
13
|
Scheurer M, Dreuw A, Epifanovsky E, Head-Gordon M, Stauch T. Modeling Molecules under Pressure with Gaussian Potentials. J Chem Theory Comput 2021; 17:583-597. [PMID: 33350311 DOI: 10.1021/acs.jctc.0c01212] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The computational modeling of molecules under high pressure is a growing research area that augments experimental high-pressure chemistry. Here, a new electronic structure method for modeling atoms and molecules under pressure, Gaussians On Surface Tesserae Simulate HYdrostatic Pressure (GOSTSHYP) approach, is introduced. In this method, a set of Gaussian potentials is distributed evenly on the van der Waals surface of the investigated chemical system, leading to a compression of the electron density and the atomic scaffold. Since no parameters other than pressure need to be specified, GOSTSHYP allows straightforward geometry optimizations and ab initio molecular dynamics simulations of chemical systems under pressure for nonexpert users. Calculated energies, bond lengths, and dipole moments under pressure fall within the range of established computational methods for high-pressure chemistry. A Diels-Alder reaction and the cyclotrimerization of acetylene showcase the ability of GOSTSHYP to model pressure-induced chemical reactions. The connection to mechanochemistry is pointed out.
Collapse
Affiliation(s)
- Maximilian Scheurer
- Interdisciplinary Center for Scientific Computing, Heidelberg University, D-69120 Heidelberg, Germany
| | - Andreas Dreuw
- Interdisciplinary Center for Scientific Computing, Heidelberg University, D-69120 Heidelberg, Germany
| | - Evgeny Epifanovsky
- Q-Chem Inc., 6601 Owens Dr, Suite 105, Pleasanton, California 94588, United States
| | - Martin Head-Gordon
- Pitzer Center for Theoretical Chemistry, University of California, Berkeley, South Dr, Berkeley, California 94720, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, California 94720, United States
| | - Tim Stauch
- Institute for Physical and Theoretical Chemistry, University of Bremen, Leobener Str. NW2, D-28359 Bremen, Germany.,Bremen Center for Computational Materials Science, University of Bremen, Am Fallturm 1, D-28359 Bremen, Germany.,MAPEX Center for Materials and Processes, University of Bremen, Bibliothekstr. 1, D-28359 Bremen, Germany
| |
Collapse
|
14
|
Chen Y, Yan X, Geng H, Sheng X, Zhang L, Wang H, Li J, Cao Y, Pan X. Prediction of Stable Ground-State Binary Sodium-Potassium Interalkalis under High Pressures. Inorg Chem 2021; 60:124-129. [PMID: 33352043 DOI: 10.1021/acs.inorgchem.0c02506] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The complex structures and electronic properties of alkali metals and their alloys provide a natural laboratory for studying the interelectronic interactions of metals under compression. A recent theoretical study (J. Phys. Chem. Lett. 2019, 10, 3006) predicted an interesting pressure-induced decomposition-recombination behavior of the Na2K compound over a pressure range of 10-500 GPa. However, a subsequent experiment (Phys. Rev. B 2020, 101, 224108) reported the formation of NaK rather than Na2K at pressures above 5.9 GPa. To address this discordance, we study the chemical stability of different stoichiometries of NaxK (x = 1/4, 1/3, 1/2, 2/3, 3/4, 4/3, 3/2, and 1-4) by an effective structure searching method combined with first-principles calculations. Na2K is calculated to be unstable at 5-35 GPa due to the decomposition reaction Na2K → NaK + Na, coinciding well with the experiment. NaK undergoes a combination-decomposition-recombination process accompanied by an opposite charge-transfer behavior between Na and K with pressure. Besides NaK, two hitherto unknown compounds NaK3 and Na3K2 are uncovered. NaK3 is a typical metallic alloy, while Na3K2 is an electride with strong interstitial electron localization.
Collapse
Affiliation(s)
- Yangmei Chen
- School of Science, Jiangxi University of Science and Technology, Ganzhou 341000, Jiangxi, People's Republic of China
| | - Xiaozhen Yan
- School of Science, Jiangxi University of Science and Technology, Ganzhou 341000, Jiangxi, People's Republic of China.,National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, CAEP, P.O. Box 919-102, Mianyang 621900, Sichuan, People's Republic of China
| | - Huayun Geng
- National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, CAEP, P.O. Box 919-102, Mianyang 621900, Sichuan, People's Republic of China
| | - Xiaowei Sheng
- Department of Physics, Anhui Normal University, Anhui 241000, Wuhu, People's Republic of China
| | - Leilei Zhang
- National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, CAEP, P.O. Box 919-102, Mianyang 621900, Sichuan, People's Republic of China
| | - Hao Wang
- National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, CAEP, P.O. Box 919-102, Mianyang 621900, Sichuan, People's Republic of China
| | - Jinglong Li
- National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, CAEP, P.O. Box 919-102, Mianyang 621900, Sichuan, People's Republic of China
| | - Ye Cao
- National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, CAEP, P.O. Box 919-102, Mianyang 621900, Sichuan, People's Republic of China
| | - Xiaolong Pan
- National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, CAEP, P.O. Box 919-102, Mianyang 621900, Sichuan, People's Republic of China
| |
Collapse
|
15
|
Abstract
Chloroform (CHCl3) and dichloromethane (CH2Cl2) are model systems for the study of intermolecular interactions, such as hydrogen bonds and halogen–halogen interactions. Here we report a joint computational (density-functional perturbation theory (DFPT) modelling) and experimental (Raman scattering) study on the behaviour of the crystals of these compounds up to a pressure of 32 GPa. Comparing the experimental information on the Raman band positions and intensities with the results of calculations enabled us to characterize the pressure-induced evolution of the crystal structure of both compounds. We find that the previously proposed P63 phase of CHCl3 is in fact a metastable structure, and that up to 32 GPa the ambient-pressure Pnma structure is the ground state polymorph of this compound. For CH2Cl2 we confirm the stability of the ambient-pressure Pbcn structure up to 32 GPa. We show that the high-pressure evolution of the crystal geometry of CHCl3 in the Pnma structure is a result of the subtle balance between dipole–dipole interactions, hydrogen bonds and Cl···Cl contacts. For CH2Cl2 (Pbcn structure) the dipole–dipole interactions and hydrogen bonds are the main factors influencing the pressure-induced changes in the geometry.
Collapse
|