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Akerman MS, Sagi R, Iny H, Asscher M. Distribution of Weakly Interacting Atoms and Molecules in Low-Temperature Amorphous Solid Water. J Phys Chem A 2022; 126:8037-8048. [PMID: 36260925 DOI: 10.1021/acs.jpca.2c06137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Understanding the distribution and mixing of atoms and molecules in amorphous solid water (ASW) at low temperatures is relevant to the exploration of the astrochemical environment in the interstellar medium (ISM) that leads to the formation of new complex molecules. In this study, a combination of temperature programmed desorption (ΔP-TPD) experiments and Ne+ ion sputtering is used to determine the extent of mixing and distribution of guest atoms and molecules within thin ASW films deposited at 35 K on a Ru(0001) substrate, prior to sputtering. The mixing of krypton atoms and methyl chloride molecules within thin ASW films is directed by the physical properties of the respective species and the nature of their interaction with the host water molecules. While the Kr-H2O interaction may be described as a weak van der Waals attraction, the CD3Cl-H2O interaction can be characterized as weakly hydrophobic in nature. This leads to differences in the level of homogeneity in mixing and distribution of the guest species in the ASW film. Both krypton atoms and methyl chloride molecules reveal a propensity to migrate toward the ASW-vacuum interface. The krypton atoms migrate through both diffusion and displacement by incoming H2O molecules, while the methyl chloride molecules tend to move toward the vacuum interface primarily via displacement. This behavior results in more homogeneous mixing of Kr in ASW at 35 K compared to the dipole moment containing molecule CD3Cl. As a general outcome of our study, it is observed that mixing in ASW at low temperatures is more homogeneous when the guest atom/molecule is inert and does not possess a constant dipole moment.
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Affiliation(s)
- Michelle Sykes Akerman
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmund J. Safra Campus Givat Ram, Jerusalem 91904, Israel
| | - Roey Sagi
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmund J. Safra Campus Givat Ram, Jerusalem 91904, Israel
| | - Hiley Iny
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmund J. Safra Campus Givat Ram, Jerusalem 91904, Israel
| | - Micha Asscher
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmund J. Safra Campus Givat Ram, Jerusalem 91904, Israel
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Mei B, Schweizer KS. Theory of the effect of external stress on the activated dynamics and transport of dilute penetrants in supercooled liquids and glasses. J Chem Phys 2021; 155:054505. [PMID: 34364324 DOI: 10.1063/5.0056920] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
We generalize the self-consistent cooperative hopping theory for a dilute spherical penetrant or tracer activated dynamics in dense metastable hard sphere fluids and glasses to address the effect of external stress, the consequences of which are systematically established as a function of matrix packing fraction and penetrant-to-matrix size ratio. All relaxation processes speed up under stress, but the difference between the penetrant and matrix hopping (alpha relaxation) times decreases significantly with stress corresponding to less time scale decoupling. A dynamic crossover occurs at a critical "slaving onset" stress beyond which the matrix activated hopping relaxation time controls the penetrant hopping time. This characteristic stress increases (decreases) exponentially with packing fraction (size ratio) and can be well below the absolute yield stress of the matrix. Below the slaving onset, the penetrant hopping time is predicted to vary exponentially with stress, differing from the power law dependence of the pure matrix alpha time due to system-specificity of the stress-induced changes in the penetrant local cage and elastic barriers. An exponential growth of the penetrant alpha relaxation time with size ratio under stress is predicted, and at a fixed matrix packing fraction, the exponential relation between penetrant hopping time and stress for different size ratios can be collapsed onto a master curve. Direct connections between the short- and long-time activated penetrant dynamics and between the penetrant (or matrix) alpha relaxation time and matrix thermodynamic dimensionless compressibility are also predicted. The presented results should be testable in future experiments and simulations.
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Affiliation(s)
- Baicheng Mei
- Department of Materials Science, University of Illinois, Urbana, Illinois 61801, USA
| | - Kenneth S Schweizer
- Department of Materials Science, University of Illinois, Urbana, Illinois 61801, USA
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Mei B, Schweizer KS. Activated penetrant dynamics in glass forming liquids: size effects, decoupling, slaving, collective elasticity and correlation with matrix compressibility. SOFT MATTER 2021; 17:2624-2639. [PMID: 33528485 DOI: 10.1039/d0sm02215b] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We employ the microscopic self-consistent cooperative hopping theory of penetrant activated dynamics in glass forming viscous liquids and colloidal suspensions to address new questions over a wide range of high matrix packing fractions and penetrant-to-matrix particle size ratios. The focus is on the mean activated relaxation time of smaller tracers in a hard sphere fluid of larger particle matrices. This quantity also determines the penetrant diffusion constant and connects directly with the structural relaxation time probed in an incoherent dynamic structure factor measurement. The timescale of the non-activated fast dissipative process is also studied and is predicted to follow power laws with the contact value of the penetrant-matrix pair correlation function and the penetrant-matrix size ratio. For long time penetrant relaxation, in the relatively lower packing fraction metastable regime the local cage barriers are dominant and matrix collective elasticity effects unimportant. As packing fraction and/or penetrant size grows, much higher barriers emerge and the collective elasticity associated with the correlated matrix dynamic displacement that facilitates penetrant hopping becomes important. This results in a non-monotonic variation with packing fraction of the degree of decoupling between the matrix and penetrant alpha relaxation times. The conditions required for penetrant hopping to become slaved to the matrix alpha process are determined, which depend mainly on the penetrant to matrix particle size ratio. By analyzing the absolute and relative importance of the cage and elastic barriers we establish a mechanistic understanding of the origin of the predicted exponential growth of the penetrant hopping time with size ratio predicted at very high packing fractions. A dynamics-thermodynamics power law connection between the penetrant activation barrier and the matrix dimensionless compressibility is established as a prediction of theory, with different scaling exponents depending on whether matrix collective elasticity effects are important. Quantitative comparisons with simulations of the penetrant relaxation time, diffusion constant, and transient localization length of tracers in dense colloidal suspensions and cold viscous liquids reveal good agreements. Multiple new predictions are made that are testable via future experiments and simulations. Extension of the theoretical approach to more complex systems of high experimental interest (nonspherical molecules, semiflexible polymers, crosslinked networks) interacting via variable hard or soft repulsions and/or short range attractions is possible, including under external deformation.
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Affiliation(s)
- Baicheng Mei
- Department of Materials Science, University of Illinois, Urbana, IL 61801, USA. and Materials Research Laboratory, University of Illinois, Urbana, IL 61801, USA
| | - Kenneth S Schweizer
- Department of Materials Science, University of Illinois, Urbana, IL 61801, USA. and Materials Research Laboratory, University of Illinois, Urbana, IL 61801, USA and Department of Chemistry, University of Illinois, Urbana, IL 61801, USA and Department of Chemical & Biomolecular Engineering, University of Illinois, Urbana, IL 61801, USA
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Effect of Pd doping on CH 4 reactivity over Co 3 O 4 catalysts from density-functional theory calculations. CHINESE JOURNAL OF CATALYSIS 2017. [DOI: 10.1016/s1872-2067(17)62817-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Zhang R, Schweizer KS. Theory of activated penetrant diffusion in viscous fluids and colloidal suspensions. J Chem Phys 2015; 143:144906. [PMID: 26472397 DOI: 10.1063/1.4932679] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We heuristically formulate a microscopic, force level, self-consistent nonlinear Langevin equation theory for activated barrier hopping and non-hydrodynamic diffusion of a hard sphere penetrant in very dense hard sphere fluid matrices. Penetrant dynamics is controlled by a rich competition between force relaxation due to penetrant self-motion and collective matrix structural (alpha) relaxation. In the absence of penetrant-matrix attraction, three activated dynamical regimes are predicted as a function of penetrant-matrix size ratio which are physically distinguished by penetrant jump distance and the nature of matrix motion required to facilitate its hopping. The penetrant diffusion constant decreases the fastest with size ratio for relatively small penetrants where the matrix effectively acts as a vibrating amorphous solid. Increasing penetrant-matrix attraction strength reduces penetrant diffusivity due to physical bonding. For size ratios approaching unity, a distinct dynamical regime emerges associated with strong slaving of penetrant hopping to matrix structural relaxation. A crossover regime at intermediate penetrant-matrix size ratio connects the two limiting behaviors for hard penetrants, but essentially disappears if there are strong attractions with the matrix. Activated penetrant diffusivity decreases strongly with matrix volume fraction in a manner that intensifies as the size ratio increases. We propose and implement a quasi-universal approach for activated diffusion of a rigid atomic/molecular penetrant in a supercooled liquid based on a mapping between the hard sphere system and thermal liquids. Calculations for specific systems agree reasonably well with experiments over a wide range of temperature, covering more than 10 orders of magnitude of variation of the penetrant diffusion constant.
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Affiliation(s)
- Rui Zhang
- Department of Materials Science and Frederick Seitz Materials Research Laboratory, University of Illinois, 1304 West Green Street, Urbana, Illinois 61801, USA
| | - Kenneth S Schweizer
- Department of Materials Science and Frederick Seitz Materials Research Laboratory, University of Illinois, 1304 West Green Street, Urbana, Illinois 61801, USA
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Smith RS, May RA, Kay BD. Probing Toluene and Ethylbenzene Stable Glass Formation Using Inert Gas Permeation. J Phys Chem Lett 2015; 6:3639-3644. [PMID: 26722735 DOI: 10.1021/acs.jpclett.5b01611] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Inert gas permeation is used to investigate the formation of stable glasses of toluene and ethylbenzene. The effect of deposition temperature (T(dep)) on the kinetic stability of the vapor deposited glasses is determined using Kr desorption spectra from within sandwich layers of either toluene or ethylbenzene. The results for toluene show that the most stable glass is formed at T(dep) = 0.92 T(g), although glasses with a kinetic stability within 50% of the most stable glass were found with deposition temperatures from 0.85 to 0.95 T(g). Similar results were found for ethylbenzene, which formed its most stable glass at 0.91 T(g) and formed stable glasses from 0.81 to 0.96 T(g). These results are consistent with recent calorimetric studies and demonstrate that the inert gas permeation technique provides a direct method to observe the onset of molecular translation motion that accompanies the glass to supercooled liquid transition.
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Affiliation(s)
- R Scott Smith
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory , Richland, Washington 99352, United States
| | - R Alan May
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory , Richland, Washington 99352, United States
| | - Bruce D Kay
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory , Richland, Washington 99352, United States
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May RA, Smith RS, Kay BD. Mobility of Supercooled Liquid Toluene, Ethylbenzene, and Benzene near Their Glass Transition Temperatures Investigated Using Inert Gas Permeation. J Phys Chem A 2013; 117:11881-9. [DOI: 10.1021/jp403093e] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- R. Alan May
- Fundamental and Computational
Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington
99352, United States
| | - R. Scott Smith
- Fundamental and Computational
Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington
99352, United States
| | - Bruce D. Kay
- Fundamental and Computational
Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington
99352, United States
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Alan May R, Scott Smith R, Kay BD. The release of trapped gases from amorphous solid water films. II. “Bottom-up” induced desorption pathways. J Chem Phys 2013; 138:104502. [DOI: 10.1063/1.4793312] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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May RA, Smith RS, Kay BD. The release of trapped gases from amorphous solid water films. I. “Top-down” crystallization-induced crack propagation probed using the molecular volcano. J Chem Phys 2013; 138:104501. [DOI: 10.1063/1.4793311] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Matthiesen J, Scott Smith R, Kay BD. Probing the mobility of supercooled liquid 3-methylpentane at temperatures near the glass transition using rare gas permeation. J Chem Phys 2012; 137:064509. [DOI: 10.1063/1.4743902] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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11
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Smith RS, Kay BD. Breaking Through the Glass Ceiling: Recent Experimental Approaches to Probe the Properties of Supercooled Liquids near the Glass Transition. J Phys Chem Lett 2012; 3:725-30. [PMID: 26286280 DOI: 10.1021/jz201710z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Experimental measurements of the properties of supercooled liquids at temperatures near their glass transition temperatures, Tg, are requisite for understanding the behavior of glasses and amorphous solids. Unfortunately, many supercooled molecular liquids rapidly crystallize at temperatures far above their Tg, making such measurements difficult to nearly impossible. In this Perspective, we discuss some recent alternative approaches to obtain experimental data in the temperature regime near Tg. These new approaches may yield the additional experimental data necessary to test current theoretical models of the dynamical slowdown that occurs in supercooled liquids approaching the glass transition.
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Affiliation(s)
- 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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Smith RS, Matthiesen J, Knox J, Kay BD. Crystallization Kinetics and Excess Free Energy of H2O and D2O Nanoscale Films of Amorphous Solid Water. J Phys Chem A 2011; 115:5908-17. [DOI: 10.1021/jp110297q] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- 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
| | - Jesper Matthiesen
- Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, P.O. Box 999, Mail Stop K8-88, Richland Washington 99352, United States
| | - Jake Knox
- 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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May RA, Smith RS, Kay BD. Probing the interaction of amorphous solid water on a hydrophobic surface: dewetting and crystallization kinetics of ASW on carbon tetrachloride. Phys Chem Chem Phys 2011; 13:19848-55. [DOI: 10.1039/c1cp21855g] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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14
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Smith RS, Matthiesen J, Kay BD. Measuring diffusivity in supercooled liquid nanoscale films using inert gas permeation. I. Kinetic model and scaling methods. J Chem Phys 2010; 133:174504. [DOI: 10.1063/1.3497654] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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