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Chowdhury S, Ghorai PK, Maity NC, Kumbhakar K, Biswas R. Identical Diffusion Distributions and Co-Cluster Formation Dictate Azeotrope Formation: Microscopic Evidences and Experimental Signatures. J Phys Chem B 2023; 127:8417-8431. [PMID: 37735851 DOI: 10.1021/acs.jpcb.3c02486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/23/2023]
Abstract
What selects azeotropic pairs and governs the azeotropic conditions (composition and temperature) is an open and intriguing question. A combined simulation and experimental work presented here investigates this by considering ethanol-water mixtures. We find identical distributions of center-of-mass diffusion coefficients for ethanol and water molecules under the azeotropic condition (95.5 wt % ethanol +4.5 wt % water, Tazeo = 351.1K). Moreover, the particle displacements show strong interspecies correlations at Tazeo. Interestingly, simulated reorientation time distributions become identical at Tazeo but at a composition different from that at which the translational diffusion distributions overlapped. Cluster analyses indicate that solutions at Tazeo with xwater ≤ 15 wt % are more microheterogeneous than those with higher water content, although no anomaly in the composition-dependent solution structural properties was detected. Ethanol-water and ethanol-ethanol interaction energies show pronounced nonideal composition dependence, but the size of the relative fluctuations in them remained small (∼0.5kBT). Rare water-water H-bonding, predominant water-ethanol H-bonding, and a sizable population of "free" water molecules characterize the azeotropic solutions. The red edge excitation spectroscopic (REES) measurements with a dissolved anionic fluorescent dye, coumarin343 (C343), support the predicted solution microheterogeneity by showing a nonmonotonic composition dependence of the excitation energy-induced changes in the fluorescence emission spectral frequencies and bandwidths, the largest changes being under the azeotropic condition. Subsequent dynamic anisotropy measurements reveal a nonmonotonic composition dependence of C343 rotation times with a peak under the azeotropic condition. In summary, equalization of the component translational diffusion coefficients and solution microheterogeneity with regular composition dependence of the solution structure appear to characterize the ethanol-water azeotrope.
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Affiliation(s)
- Shrestha Chowdhury
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741246, India
| | - Pradip Kr Ghorai
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741246, India
| | - Narayan Chandra Maity
- Department of Chemical and Biological Sciences, S.N. Bose National Centre for Basic Sciences, Kolkata 700106, India
| | - Kajal Kumbhakar
- Department of Chemical and Biological Sciences, S.N. Bose National Centre for Basic Sciences, Kolkata 700106, India
| | - Ranjit Biswas
- Department of Chemical and Biological Sciences, S.N. Bose National Centre for Basic Sciences, Kolkata 700106, India
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2
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Liu J, Feng RR, Zhou L, Gai F, Zhang W. Photoenhancement of the C≡N Stretching Vibration Intensity of Aromatic Nitriles. J Phys Chem Lett 2022; 13:9745-9751. [PMID: 36222647 DOI: 10.1021/acs.jpclett.2c02418] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The C≡N stretching vibration is a versatile infrared (IR) reporter that is useful for a wide range of applications. Aiming to further expand its spectroscopic utility, herein, we show that, using 4-cyanoindole and 4-cyano-7-azaindole as examples, photoexcitation can significantly shift the frequency (νCN) and enhance the molar extinction coefficient (εCN) of this vibrational mode of aromatic nitriles and that, for these indole derivatives, the enhancement factor can reach 13. Moreover, we find that while solvent relaxation at the excited electronic state(s) always leads to an increase in εCN, its effect on νCN depends on the solute and the solvent. Taken together, these results demonstrate that solvent relaxation can differently affect the local environment of the nitrile group and its conjugation with the indole ring and, more importantly, that the C≡N stretching vibration can serve as a sensitive IR probe of charge and electron transfer processes in which an aromatic nitrile is involved.
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Affiliation(s)
- Jingsong Liu
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875, China
| | - Ran-Ran Feng
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Liang Zhou
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875, China
| | - Feng Gai
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Wenkai Zhang
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875, China
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3
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Cai J, Griesbach C, Thevamaran R. Extreme Dynamic Performance of Nanofiber Mats under Supersonic Impacts Mediated by Interfacial Hydrogen Bonds. ACS NANO 2021; 15:19945-19955. [PMID: 34870968 DOI: 10.1021/acsnano.1c07465] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Achieving extreme dynamic performance in nanofibrous materials requires synergistic exploitation of intrinsic nanofiber properties and inter-fiber interactions. Regardless of the superior intrinsic stiffness and strength of carbon nanotubes (CNTs), the weak nature of van der Waals interactions limits the CNT mats from achieving greater performance. We present an efficient approach to augment the inter-fiber interactions by introducing aramid nanofiber (ANF) links between CNTs, which forms stronger and reconfigurable interfacial hydrogen bonds and π-π stacking interactions, leading to synergistic performance improvement with failure retardation. Under supersonic impacts, strengthened interactions in CNT mats enhance their specific energy absorption up to 3.6 MJ/kg, which outperforms widely used bulk Kevlar-fiber-based protective materials. The distinct response time scales of hydrogen bond breaking and reformation at ultrahigh-strain-rate (∼107-108 s-1) deformations additionally manifest a strain-rate-dependent dynamic performance enhancement. Our findings show the potential of nanofiber mats augmented with interfacial dynamic bonds─such as the hydrogen bonds─as low-density structural materials with superior specific properties and high-temperature stability for extreme engineering applications.
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Affiliation(s)
- Jizhe Cai
- Department of Engineering Physics, University of Wisconsin─Madison, Madison, Wisconsin 53706, United States
| | - Claire Griesbach
- Department of Engineering Physics, University of Wisconsin─Madison, Madison, Wisconsin 53706, United States
| | - Ramathasan Thevamaran
- Department of Engineering Physics, University of Wisconsin─Madison, Madison, Wisconsin 53706, United States
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4
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5
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Brünker P, Domenianni LI, Fleck N, Lindner J, Schiemann O, Vöhringer P. Intramolecular O-H⋯S hydrogen bonding in threefold symmetry: Line broadening dynamics from ultrafast 2DIR-spectroscopy and ab initio calculations. J Chem Phys 2021; 154:134305. [PMID: 33832237 DOI: 10.1063/5.0047885] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The dynamics of intramolecular hydrogen-bonding involving sulfur atoms as acceptors is studied using two-dimensional infrared (2DIR) spectroscopy. The molecular system is a tertiary alcohol whose donating hydroxy group is embedded in a hydrogen-bond potential with torsional C3-symmetry about the carbon-oxygen bond. The linear and 2DIR-spectra recorded in the OH-stretching region of the alcohol can be simulated very well using Kubo's line shape theory based on the cumulant expansion for evaluating the linear and nonlinear optical response functions. The correlation function for OH-stretching frequency fluctuations reveals an ultrafast component decaying with a time constant of 700 fs, which is in line with the apparent decay of the center line slopes averaged over absorption and bleach/emission signals. In addition, a quasi-static inhomogeneity is detected, which prevents the 2DIR line shape to fully homogenize within the observation window of 4 ps. The experimental data were then analyzed in more detail using a full ab initio approach that merges time-dependent structural information from classical molecular dynamics (MD) simulations with an OH-stretching frequency map derived from density functional theory (DFT). The latter method was also used to obtain a complementary transition dipole map to account for non-Condon effects. The 2DIR-spectra obtained from the MD/DFT method are in good agreement with the experimental data at early waiting delays, thereby corroborating an assignment of the fast decay of the correlation function to the dynamics of hydrogen-bond breakage and formation.
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Affiliation(s)
- Paul Brünker
- Institut für Physikalische und Theoretische Chemie, Rheinische Friedrich-Wilhelms-Universität, Wegelerstraße 12, 53115 Bonn, Germany
| | - Luis I Domenianni
- Institut für Physikalische und Theoretische Chemie, Rheinische Friedrich-Wilhelms-Universität, Wegelerstraße 12, 53115 Bonn, Germany
| | - Nico Fleck
- Institut für Physikalische und Theoretische Chemie, Rheinische Friedrich-Wilhelms-Universität, Wegelerstraße 12, 53115 Bonn, Germany
| | - Jörg Lindner
- Institut für Physikalische und Theoretische Chemie, Rheinische Friedrich-Wilhelms-Universität, Wegelerstraße 12, 53115 Bonn, Germany
| | - Olav Schiemann
- Institut für Physikalische und Theoretische Chemie, Rheinische Friedrich-Wilhelms-Universität, Wegelerstraße 12, 53115 Bonn, Germany
| | - Peter Vöhringer
- Institut für Physikalische und Theoretische Chemie, Rheinische Friedrich-Wilhelms-Universität, Wegelerstraße 12, 53115 Bonn, Germany
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6
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7
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Holt GT, Jou JD, Gill NP, Lowegard AU, Martin JW, Madden DR, Donald BR. Computational Analysis of Energy Landscapes Reveals Dynamic Features That Contribute to Binding of Inhibitors to CFTR-Associated Ligand. J Phys Chem B 2019; 123:10441-10455. [PMID: 31697075 DOI: 10.1021/acs.jpcb.9b07278] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The CFTR-associated ligand PDZ domain (CALP) binds to the cystic fibrosis transmembrane conductance regulator (CFTR) and mediates lysosomal degradation of mature CFTR. Inhibition of this interaction has been explored as a therapeutic avenue for cystic fibrosis. Previously, we reported the ensemble-based computational design of a novel peptide inhibitor of CALP, which resulted in the most binding-efficient inhibitor to date. This inhibitor, kCAL01, was designed using osprey and evinced significant biological activity in in vitro cell-based assays. Here, we report a crystal structure of kCAL01 bound to CALP and compare structural features against iCAL36, a previously developed inhibitor of CALP. We compute side-chain energy landscapes for each structure to not only enable approximation of binding thermodynamics but also reveal ensemble features that contribute to the comparatively efficient binding of kCAL01. Finally, we compare the previously reported design ensemble for kCAL01 vs the new crystal structure and show that, despite small differences between the design model and crystal structure, significant biophysical features that enhance inhibitor binding are captured in the design ensemble. This suggests not only that ensemble-based design captured thermodynamically significant features observed in vitro, but also that a design eschewing ensembles would miss the kCAL01 sequence entirely.
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Affiliation(s)
- Graham T Holt
- Department of Computer Science , Duke University , Durham , North Carolina 27708 , United States.,Program in Computational Biology and Bioinformatics , Duke University , Durham , North Carolina 27708 , United States
| | - Jonathan D Jou
- Department of Computer Science , Duke University , Durham , North Carolina 27708 , United States
| | - Nicholas P Gill
- Department of Biochemistry & Cell Biology , Geisel School of Medicine at Dartmouth , Hanover , New Hampshire 03755 , United States
| | - Anna U Lowegard
- Department of Computer Science , Duke University , Durham , North Carolina 27708 , United States.,Program in Computational Biology and Bioinformatics , Duke University , Durham , North Carolina 27708 , United States
| | - Jeffrey W Martin
- Department of Computer Science , Duke University , Durham , North Carolina 27708 , United States
| | - Dean R Madden
- Department of Biochemistry & Cell Biology , Geisel School of Medicine at Dartmouth , Hanover , New Hampshire 03755 , United States
| | - Bruce R Donald
- Department of Computer Science , Duke University , Durham , North Carolina 27708 , United States.,Department of Biochemistry , Duke University , Durham , North Carolina 27710 , United States.,Department of Chemistry , Duke University , Durham , North Carolina 27710 , United States
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8
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Talebian S, Mehrali M, Taebnia N, Pennisi CP, Kadumudi FB, Foroughi J, Hasany M, Nikkhah M, Akbari M, Orive G, Dolatshahi‐Pirouz A. Self-Healing Hydrogels: The Next Paradigm Shift in Tissue Engineering? ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2019; 6:1801664. [PMID: 31453048 PMCID: PMC6702654 DOI: 10.1002/advs.201801664] [Citation(s) in RCA: 228] [Impact Index Per Article: 45.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Revised: 03/04/2019] [Indexed: 05/18/2023]
Abstract
Given their durability and long-term stability, self-healable hydrogels have, in the past few years, emerged as promising replacements for the many brittle hydrogels currently being used in preclinical or clinical trials. To this end, the incompatibility between hydrogel toughness and rapid self-healing remains unaddressed, and therefore most of the self-healable hydrogels still face serious challenges within the dynamic and mechanically demanding environment of human organs/tissues. Furthermore, depending on the target tissue, the self-healing hydrogels must comply with a wide range of properties including electrical, biological, and mechanical. Notably, the incorporation of nanomaterials into double-network hydrogels is showing great promise as a feasible way to generate self-healable hydrogels with the above-mentioned attributes. Here, the recent progress in the development of multifunctional and self-healable hydrogels for various tissue engineering applications is discussed in detail. Their potential applications within the rapidly expanding areas of bioelectronic hydrogels, cyborganics, and soft robotics are further highlighted.
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Affiliation(s)
- Sepehr Talebian
- Intelligent Polymer Research InstituteARC Centre of Excellence for Electromaterials ScienceAIIM FacilityUniversity of WollongongNSW2522Australia
- Illawarra Health and Medical Research InstituteUniversity of WollongongWollongongNSW2522Australia
| | - Mehdi Mehrali
- DTU NanotechCenter for Intestinal Absorption and Transport of BiopharmaceuticalsTechnical University of DenmarkLyngby2800KgsDenmark
| | - Nayere Taebnia
- DTU NanotechCenter for Intestinal Absorption and Transport of BiopharmaceuticalsTechnical University of DenmarkLyngby2800KgsDenmark
| | - Cristian Pablo Pennisi
- Laboratory for Stem Cell ResearchDepartment of Health Science and TechnologyAalborg UniversityFredrik Bajers vej 3B9220AalborgDenmark
| | - Firoz Babu Kadumudi
- DTU NanotechCenter for Intestinal Absorption and Transport of BiopharmaceuticalsTechnical University of DenmarkLyngby2800KgsDenmark
| | - Javad Foroughi
- Intelligent Polymer Research InstituteARC Centre of Excellence for Electromaterials ScienceAIIM FacilityUniversity of WollongongNSW2522Australia
- Illawarra Health and Medical Research InstituteUniversity of WollongongWollongongNSW2522Australia
| | - Masoud Hasany
- DTU NanotechCenter for Intestinal Absorption and Transport of BiopharmaceuticalsTechnical University of DenmarkLyngby2800KgsDenmark
| | - Mehdi Nikkhah
- School of Biological Health and Systems Engineering (SBHSE)Arizona State UniversityTempeAZ85287USA
| | - Mohsen Akbari
- Laboratory for Innovations in MicroEngineering (LiME)Department of Mechanical EngineeringUniversity of VictoriaVictoriaBCV8P 5C2Canada
- Center for Biomedical ResearchUniversity of Victoria3800VictoriaCanada
- Center for Advanced Materials and Related TechnologiesUniversity of Victoria3800VictoriaCanada
| | - Gorka Orive
- NanoBioCel GroupLaboratory of PharmaceuticsSchool of PharmacyUniversity of the Basque Country UPV/EHUPaseo de la Universidad 701006Vitoria‐GasteizSpain
- Biomedical Research Networking Centre in BioengineeringBiomaterials, and Nanomedicine (CIBER‐BBN)Vitoria‐Gasteiz28029Spain
- University Institute for Regenerative Medicine and Oral Implantology – UIRMI (UPV/EHU‐Fundación Eduardo Anitua)Vitoria01007Spain
- BTI Biotechnology InstituteVitoria01007Spain
| | - Alireza Dolatshahi‐Pirouz
- DTU NanotechCenter for Intestinal Absorption and Transport of BiopharmaceuticalsTechnical University of DenmarkLyngby2800KgsDenmark
- Department of Dentistry‐Regenerative BiomaterialsRadboud University Medical CenterPhilips van Leydenlaan 25Nijmegen6525EXThe Netherlands
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9
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Mesele OO, Thompson WH. A "Universal" Spectroscopic Map for the OH Stretching Mode in Alcohols. J Phys Chem A 2017; 121:5823-5833. [PMID: 28715218 DOI: 10.1021/acs.jpca.7b05836] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Empirical maps are presented for the OH stretching vibrations in neat alcohols in which the relevant spectroscopic quantities are expressed in terms of the electric field exerted on the hydrogen atom by the surrounding liquid. It is found, by examination of the four lowest linear alcohols, methanol, ethanol, n-propanol, and n-butanol, that a single map can be used for alcohols with different alkyl groups. This "universal" map is in very good agreement with maps optimized for the individual alcohols but differs from those previously developed for water. This suggests that one map can be used for all alcohols, perhaps even those not examined in the present study. The universal map gives IR lineshapes in good agreement with measured spectra for isotopically dilute methanol and ethanol, while the two-dimensional IR photon echo spectra give results that differ from experiments. The role of non-Condon effects, reorientation dynamics, hydrogen bonding, and spectral diffusion is discussed.
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Affiliation(s)
- Oluwaseun O Mesele
- Department of Chemistry, University of Kansas , Lawrence, Kansas 66045, United States
| | - Ward H Thompson
- Department of Chemistry, University of Kansas , Lawrence, Kansas 66045, United States
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10
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Foo GS, Hu G, Hood ZD, Li M, Jiang DE, Wu Z. Kinetics and Mechanism of Methanol Conversion over Anatase Titania Nanoshapes. ACS Catal 2017. [DOI: 10.1021/acscatal.7b01456] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Guo Shiou Foo
- Chemical
Sciences Division and Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Guoxiang Hu
- Department
of Chemistry, University of California, Riverside, California 92521, United States
| | - Zachary D. Hood
- School
of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Meijun Li
- Chemical
Sciences Division and Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - De-en Jiang
- Department
of Chemistry, University of California, Riverside, California 92521, United States
| | - Zili Wu
- Chemical
Sciences Division and Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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11
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Kramer PL, Giammanco CH, Fayer MD. Dynamics of water, methanol, and ethanol in a room temperature ionic liquid. J Chem Phys 2015; 142:212408. [DOI: 10.1063/1.4914156] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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12
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Mazur K, Bonn M, Hunger J. Hydrogen bond dynamics in primary alcohols: a femtosecond infrared study. J Phys Chem B 2015; 119:1558-66. [PMID: 25531023 DOI: 10.1021/jp509816q] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hydrogen-bonded liquids are excellent solvents, in part due to the highly dynamic character of the directional interaction associated with the hydrogen bond. Here we study the vibrational and reorientational dynamics of deuterated hydroxyl groups in various primary alcohols using polarization-resolved femtosecond infrared spectroscopy. We show that the relaxation of the OD stretch vibration is similar for ethanol and its higher homologues (∼0.9 ps), while it is appreciably faster for methanol (∼0.75 ps). The fast relaxation for methanol is attributed to strong coupling of the OD stretch vibration to the overtone of the CH3 rocking mode. Subsequent to excited state relaxation, the dissipation of the excess energy leads to structural relaxation of the alcohol liquid structure. We show that this relaxation of the H-bonded network depends on the alkyl chain length. We find that the anisotropy of the excitation decays by both thermal diffusion from excited OD groups to nonexcited molecules and reorientational motion. The reorientation is described well by a model employing two relaxation times that increase linearly with increasing alcohol size. The short reorientation time is assigned to the partial reorientation of molecules within the alcohol cluster, while the long reorientation times can be attributed to breaking and reforming of hydrogen bonds.
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Affiliation(s)
- Kamila Mazur
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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13
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Galizia M, La Manna P, Pannico M, Mensitieri G, Musto P. Methanol diffusion in polyimides: A molecular description. POLYMER 2014. [DOI: 10.1016/j.polymer.2014.01.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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14
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Kwac K, Geva E. A Mixed Quantum-Classical Molecular Dynamics Study of anti-Tetrol and syn-Tetrol Dissolved in Liquid Chloroform: Hydrogen-Bond Structure and Its Signature on the Infrared Absorption Spectrum. J Phys Chem B 2013; 117:16493-505. [DOI: 10.1021/jp4080724] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Kijeong Kwac
- Department
of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Eitan Geva
- Department
of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
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Kwac K, Geva E. A Mixed Quantum-Classical Molecular Dynamics Study of anti-Tetrol and syn-Tetrol Dissolved in Liquid Chloroform II: Infrared Emission Spectra, Vibrational Excited-State Lifetimes, and Nonequilibrium Hydrogen-Bond Dynamics. J Phys Chem B 2013; 117:14457-67. [DOI: 10.1021/jp408580n] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kijeong Kwac
- Department
of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Eitan Geva
- Department
of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
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16
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Kwac K, Geva E. Solvation Dynamics of Formylperylene Dissolved in Methanol–Acetonitrile Liquid Mixtures: A Molecular Dynamics Study. J Phys Chem B 2013; 117:9996-10006. [DOI: 10.1021/jp405818f] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Kijeong Kwac
- Department
of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Eitan Geva
- Department
of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
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17
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Olschewski M, Knop S, Lindner J, Vöhringer P. From Single Hydrogen Bonds to Extended Hydrogen-Bond Wires: Low-Dimensional Model Systems for Vibrational Spectroscopy of Associated Liquids. Angew Chem Int Ed Engl 2013; 52:9634-54. [DOI: 10.1002/anie.201210009] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Indexed: 11/06/2022]
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18
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Olschewski M, Knop S, Lindner J, Vöhringer P. Von einzelnen H-Brücken zu ausgedehnten H-verbrückten Drähten: niederdimensionale Modellsysteme für die Schwingungsspektroskopie vernetzter Flüssigkeiten. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201210009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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19
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Kwac K, Geva E. A Mixed Quantum-Classical Molecular Dynamics Study of the Hydroxyl Stretch in Methanol/Carbon Tetrachloride Mixtures III: Nonequilibrium Hydrogen-Bond Dynamics and Infrared Pump–Probe Spectra. J Phys Chem B 2013; 117:7737-49. [DOI: 10.1021/jp403726t] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kijeong Kwac
- Department
of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Eitan Geva
- Department
of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
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20
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Isomerization around C–C and C–O bonds in 1-propanol: Collisional relaxation in supersonic jets and selective IR photo-isomerization in cryogenic matrices. J Mol Struct 2012. [DOI: 10.1016/j.molstruc.2011.12.034] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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21
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Anna JM, Baiz CR, Ross MR, McCanne R, Kubarych KJ. Ultrafast equilibrium and non-equilibrium chemical reaction dynamics probed with multidimensional infrared spectroscopy. INT REV PHYS CHEM 2012. [DOI: 10.1080/0144235x.2012.716610] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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22
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Jiang R, Sibert EL. Surface hopping simulation of vibrational predissociation of methanol dimer. J Chem Phys 2012; 136:224104. [DOI: 10.1063/1.4724219] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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23
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Borek J, Perakis F, Kläsi F, Garrett-Roe S, Hamm P. Azide–water intermolecular coupling measured by two-color two-dimensional infrared spectroscopy. J Chem Phys 2012; 136:224503. [DOI: 10.1063/1.4726407] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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24
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Kwac K, Geva E. Mixed quantum-classical molecular dynamics study of the hydroxyl stretch in methanol/carbon-tetrachloride mixtures II: excited state hydrogen bonding structure and dynamics, infrared emission spectrum, and excited state lifetime. J Phys Chem B 2012; 116:2856-66. [PMID: 22283660 DOI: 10.1021/jp211792j] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We present a mixed quantum-classical molecular dynamics study of the hydrogen-bonding structure and dynamics of a vibrationally excited hydroxyl stretch in methanol/carbon-tetrachloride mixtures. The adiabatic Hamiltonian of the quantum-mechanical hydroxyl is diagonalized on-the-fly to obtain the ground and first-excited adiabatic energy levels and wave functions which depend parametrically on the instantaneous configuration of the classical degrees of freedom. The dynamics of the classical degrees of freedom are determined by Hellmann-Feynman forces obtained by taking the expectation value of the force with respect to the ground or excited vibrational wave functions. Polarizable force fields are used which were previously shown to reproduce the experimental infrared absorption spectrum rather well, for different isotopomers and over a wide composition range [Kwac, K.; Geva, E. J. Phys. Chem. B 2011, 115, 9184]. We show that the agreement of the absorption spectra with experiment can be further improved by accounting for the dependence of the dipole moment derivatives on the configuration of the classical degrees of freedom. We find that the propensity of a methanol molecule to form hydrogen bonds increases upon photoexcitation of its hydroxyl stretch, thereby leading to a sizable red-shift of the corresponding emission spectrum relative to the absorption spectrum. Treating the relaxation from the first excited to the ground state as a nonadiabatic process, and calculating its rate within the framework of Fermi's golden rule and the harmonic-Schofield quantum correction factor, we were able to predict a lifetime which is of the same order of magnitude as the experimental value. The experimental dependence of the lifetime on the transition frequency is also reproduced. Nonlinear mapping relations between the hydroxyl transition frequency and bond length in the excited state and the electric field along the hydroxyl bond axis are established. These mapping relations make it possible to reduce the computational cost of the mixed quantum-classical treatment to that of a fully classical treatment.
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Affiliation(s)
- Kijeong Kwac
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, USA.
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25
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Fenn EE, Wong DB, Giammanco CH, Fayer MD. Dynamics of Water at the Interface in Reverse Micelles: Measurements of Spectral Diffusion with Two-Dimensional Infrared Vibrational Echoes. J Phys Chem B 2011; 115:11658-70. [DOI: 10.1021/jp206903k] [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)
- Emily E. Fenn
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Daryl B. Wong
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Chiara H. Giammanco
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - M. D. Fayer
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
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26
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27
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Knop S, Jansen TLC, Lindner J, Vöhringer P. On the nature of OH-stretching vibrations in hydrogen-bonded chains: Pump frequency dependent vibrational lifetime. Phys Chem Chem Phys 2011; 13:4641-50. [DOI: 10.1039/c0cp02143a] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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28
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Pogorelov V, Doroshenko I, Uvdal P, Balevicius V, Sablinskas V. Temperature-controlled kinetics of the growth and relaxation of alcohol clusters in an argon matrix. Mol Phys 2010. [DOI: 10.1080/00268976.2010.494629] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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29
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Gao R, Wang L, Ma B, Zhan C, Qiu Y. Mg(OOCCH3)2 interface modification after sensitization to improve performance in quasi-solid dye-sensitized solar cells. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:2460-2465. [PMID: 19856906 DOI: 10.1021/la902688a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In this paper, a simple yet efficient method is proposed to improve the performance of dye-sensitized solar cells (DSCs) by modification after sensitization using Mg(OOCCH(3))(2). With modification of Mg(OOCCH(3))(2), a blue shift of the absorption peak and optical band gap were observed in the UV-vis spectrum. As shown in the Fourier transform infrared spectrum, the intermolecular hydrogen bonding of N3 dye, which caused the aggregation of dye molecules, was weakened. As shown in the I-V characteristic, the conversion efficiency of the DSCs was improved by the treatment of Mg(OOCCH(3))(2). Furthermore, the charge recombination was retarded as evidenced by the decreased dark current and the slowed decay rate of the dye excited state, which were characterized by the I-V curve in dark and transient photovoltage spectra. The mechanism of this modification process was also proposed further. Modification with Mg(OOCCH(3))(2) facilitated the electron injection from the dye molecule to the conductive band of TiO(2) by raising the excited state energy level of the dye molecule. This energy level rising was evidenced by the results of the cyclic voltammetry test and the blue shift of the optical band gap. Furthermore, Mg(OOCCH(3))(2) worked as an insulating barrier layer at the sensitized TiO(2)/electrolyte interface, thereby retarding the charge recombination in DSCs.
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Affiliation(s)
- Rui Gao
- Key Lab of Organic Optoelectronics & Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing 100084, China
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30
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Kasyanenko VM, Lin Z, Rubtsov GI, Donahue JP, Rubtsov IV. Energy transport via coordination bonds. J Chem Phys 2009; 131:154508. [DOI: 10.1063/1.3246862] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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31
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Jiang R, Sibert EL. How Do Hydrogen Bonds Break in Small Alcohol Oligomers? J Phys Chem A 2009; 113:7275-85. [DOI: 10.1021/jp8104776] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ruomu Jiang
- Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin−Madison, Madison, Wisconsin 53706
| | - Edwin L. Sibert
- Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin−Madison, Madison, Wisconsin 53706
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32
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Seehusen J, Schwarzer D, Lindner J, Vöhringer P. Equilibrium and mid-infrared driven vibrational dynamics of artificial hydrogen-bonded networks. Phys Chem Chem Phys 2009; 11:8484-95. [DOI: 10.1039/b903466h] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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33
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34
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Affiliation(s)
- Minhaeng Cho
- Department of Chemistry and Center for Multidimensional Spectroscopy, Korea University, Seoul 136-701, Korea.
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35
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Vibrational population relaxation of hydrogen-bonded phenol complexes in solution: Investigation by ultrafast infrared pump–probe spectroscopy. Chem Phys 2007. [DOI: 10.1016/j.chemphys.2007.07.025] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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36
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Gündoğdu K, Bandaria J, Nydegger M, Rock W, Cheatum CM. Relaxation and anharmonic couplings of the O-H stretching vibration of asymmetric strongly hydrogen-bonded complexes. J Chem Phys 2007; 127:044501. [PMID: 17672701 DOI: 10.1063/1.2753840] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We present infrared transient grating measurements of complexes of formic acid with pyridine and pyrazine at four excitation frequencies within the broad proton-stretching band. These experiments investigate the mechanism of the line broadening of the O-H stretching vibration. The transients show coherent oscillations that decay within a few hundred femtoseconds and population relaxation on two time scales. We fit the data using a simple model of three coupled oscillators that relax via sequential kinetics through an intermediate state. Based on this model, we conclude that the coherent oscillations result from superpositions of Fermi-resonance-coupled states involving formic acid overtone and combination states.
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Affiliation(s)
- Kenan Gündoğdu
- Chemistry Department, The University of Iowa, Iowa City, Iowa 52242, USA
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37
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Kurochkin DV, Naraharisetty SRG, Rubtsov IV. A relaxation-assisted 2D IR spectroscopy method. Proc Natl Acad Sci U S A 2007; 104:14209-14. [PMID: 17557837 PMCID: PMC1964833 DOI: 10.1073/pnas.0700560104] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2007] [Indexed: 11/18/2022] Open
Abstract
A method of two-dimensional infrared (2D IR) spectroscopy called relaxation-assisted 2D IR (RA 2DIR) is proposed that utilizes vibrational energy relaxation transport in molecules to enhance cross-peak amplitudes. This method substantially increases the range of distances accessible by 2D IR and is capable of identifying long-range connectivity patterns in molecules. RA 2DIR is illustrated in interactions among CN and CO modes in 3-cyanocoumarin and 4-acetylbenzonitrile, where the distances between the CN and CO groups are approximately 3.1 and approximately 6.5 A, respectively. A 6-fold increase in cross-peak amplitude was observed in 4-acetylbenzonitrile when the dual-frequency RA 2DIR method was used.
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Affiliation(s)
| | | | - Igor V. Rubtsov
- Department of Chemistry, Tulane University, New Orleans, LA 70118
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38
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Gulmen TS, Sibert EL. Vibrational energy relaxation of the OH(D) stretch fundamental of methanol in carbon tetrachloride. J Chem Phys 2007; 123:204508. [PMID: 16351282 DOI: 10.1063/1.2131055] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The lifetimes of the hydroxyl stretch fundamentals of two methanol isotopomers, MeOH and MeOD, in carbon tetrachloride solvent are calculated through the use of the perturbative Landau-Teller and fluctuating Landau-Teller methods. Examination of these systems allows for insight into the nature of the vibrational couplings that lead to intramolecular vibrational energy transfer. While both systems display energy transfer to nearly degenerate modes, MeOD also displays strong coupling to an off-resonant vibration. The relaxation of MeOH and MeOD occurs through transitions involving a total change in the vibrational quanta of 4 and 3, respectively. We calculate vibrational energy relaxation lifetimes of 4-5 ps for MeOH and 2-3 ps for MeOD that agree well with the experimentally determined values.
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Affiliation(s)
- Tolga S Gulmen
- Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin-Madison, Madison, WI 53706, USA
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39
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Wang Z, Pang Y, Dlott DD. Hydrogen-Bond Disruption by Vibrational Excitations in Water. J Phys Chem A 2007; 111:3196-208. [PMID: 17388394 DOI: 10.1021/jp069027g] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An excitation of the OH-stretch nu(OH) of water has unique disruptive effects on the local hydrogen bonding. The disruption is not an immediate vibrational predissociation, which is frequently the case with hydrogen-bonded clusters, but instead is a delayed disruption caused by a burst of energy from a vibrationally excited water molecule. The disruptive effects are the result of a fragile hydrogen-bonding network subjected to a large amount of vibrational energy released in a short time by the relaxation of nu(OH) stretching and delta(H2O) bending excitations. The energy of a single nu(OH) vibration distributed over one, two, or three (classical) water molecules would be enough to raise the local temperature to 1100, 700, or 570 K, respectively. Our understanding of the properties of the metastable water state having this excess energy in nearby hydrogen bonds, termed H2O*, has emerged as a result of experiments where a femtosecond IR pulse is used to pump nu(OH), which is probed by either Raman or IR spectroscopy. These experiments show that the H2O* spectrum is blue-shifted and narrowed, and the spectrum looks very much like supercritical water at approximately 600 K, which is consistent with the temperature estimates above. The H2O* is created within approximately 400 fs after nu(OH) excitation, and it relaxes with an 0.8 ps lifetime by re-formation of the disrupted hydrogen-bond network. Vibrationally excited H2O* with one quantum of excitation in the stretching mode has the same 0.8 ps lifetime, suggesting it also relaxes by hydrogen-bond re-formation.
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Affiliation(s)
- Zhaohui Wang
- School of Chemical Sciences, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
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40
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Kwac K, Lee C, Jung Y, Han J, Kwak K, Zheng J, Fayer MD, Cho M. Phenol-benzene complexation dynamics: Quantum chemistry calculation, molecular dynamics simulations, and two dimensional IR spectroscopy. J Chem Phys 2006; 125:244508. [PMID: 17199356 DOI: 10.1063/1.2403132] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Molecular dynamics (MD) simulations and quantum mechanical electronic structure calculations are used to investigate the nature and dynamics of the phenol-benzene complex in the mixed solvent, benzene/CCl4. Under thermal equilibrium conditions, the complexes are continuously dissociating and forming. The MD simulations are used to calculate the experimental observables related to the phenol hydroxyl stretching mode, i.e., the two dimensional infrared vibrational echo spectrum as a function of time, which directly displays the formation and dissociation of the complex through the growth of off-diagonal peaks, and the linear absorption spectrum, which displays two hydroxyl stretch peaks, one for the complex and one for the free phenol. The results of the simulations are compared to previously reported experimental data and are found to be in quite reasonable agreement. The electronic structure calculations show that the complex is T shaped. The classical potential used for the phenol-benzene interaction in the MD simulations is in good accord with the highest level of the electronic structure calculations. A variety of other features is extracted from the simulations including the relationship between the structure and the projection of the electric field on the hydroxyl group. The fluctuating electric field is used to determine the hydroxyl stretch frequency-frequency correlation function (FFCF). The simulations are also used to examine the number distribution of benzene and CCl4 molecules in the first solvent shell around the phenol. It is found that the distribution is not that of the solvent mole fraction of benzene. There are substantial probabilities of finding a phenol in either a pure benzene environment or a pure CCl4 environment. A conjecture is made that relates the FFCF to the local number of benzene molecules in phenol's first solvent shell.
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Affiliation(s)
- Kijeong Kwac
- Department of Chemistry, Center for Multidimensional Spectroscopy, Korea University, Seoul 136-701, Korea
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41
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Palombo F, Paolantoni M, Sassi P, Morresi A, Cataliotti RS. Spectroscopic studies of the “free” OH stretching bands in liquid alcohols. J Mol Liq 2006. [DOI: 10.1016/j.molliq.2005.11.006] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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42
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Piletic IR, Moilanen DE, Spry DB, Levinger NE, Fayer MD. Testing the Core/Shell Model of Nanoconfined Water in Reverse Micelles Using Linear and Nonlinear IR Spectroscopy. J Phys Chem A 2006; 110:4985-99. [PMID: 16610816 DOI: 10.1021/jp061065c] [Citation(s) in RCA: 269] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A core/shell model has often been used to describe water confined to the interior of reverse micelles. The validity of this model for water encapsulated in AOT/isooctane reverse micelles ranging in diameter from 1.7 to 28 nm (w0 = 2-60) and bulk water is investigated using four experimental observables: the hydroxyl stretch absorption spectra, vibrational population relaxation times, orientational relaxation rates, and spectral diffusion dynamics. The time dependent observables are measured with ultrafast infrared spectrally resolved pump-probe and vibrational echo spectroscopies. Major progressive changes appear in all observables as the system moves from bulk water to the smallest water nanopool, w0 = 2. The dynamics are readily distinguishable for reverse micelle sizes smaller than 7 nm in diameter (w0 = 20) compared to the response of bulk water. The results also demonstrate that the size dependent absorption spectra and population relaxation times can be quantitatively predicted using a core-shell model in which the properties of the core (interior of the nanopool) are taken to be those of bulk water and the properties of the shell (water associated with the headgroups) are taken to be those of w0 = 2. A weighted sum of the core and shell components reproduces the size dependent spectra and the nonexponential population relaxation dynamics. However, the same model does not reproduce the spectral diffusion and the orientational relaxation experiments. It is proposed that, when hydrogen bond structural rearrangement is involved (orientational relaxation and spectral diffusion), dynamical coupling between the shell and the core cause the water nanopool to display more homogeneous dynamics. Therefore, the absorption spectra and vibrational lifetime decays can discern different hydrogen bonding environments whereas orientational and spectral diffusion correlation functions predict that the dynamics are size dependent but not as strongly spatially dependent within a reverse micelle.
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Affiliation(s)
- Ivan R Piletic
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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43
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Kurochkin DV, Naraharisetty SRG, Rubtsov IV. Dual-frequency 2D IR on interaction of weak and strong IR modes. J Phys Chem A 2006; 109:10799-802. [PMID: 16331922 DOI: 10.1021/jp055811+] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dual-frequency 2D IR heterodyne photon-echo spectroscopy of C[triple bond]N and C=O stretching vibrational modes in 2-cyanocoumarin is reported. We have shown that the interaction among these modes provides convenient and useful structural constraints for molecules. Implementation of two pulse sequences, 4, 4, and 6 microm and 6, 6, and 4 microm, allowed the clear determination of contributions caused by vibrational relaxation. Positive correlation between C[triple bond]N and C=O frequency distributions was observed in 2-cyanocoumarin. Because C[triple bond]N modes are highly localized and have frequencies in a spectral region with minimal water absorption, the C[triple bond]N/C=O interactions have a strong potential for use as structural reporters in proteins. In addition to CN/CO peaks, the cross-peaks responsible for the C[triple bond]N/C=C interaction are also observed in the 2D IR spectra, where C=C is a coumarin ring stretching mode. We have demonstrated that 2D IR spectroscopy can utilize interactions of strong IR modes with weak local modes as structural reporters.
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Affiliation(s)
- Dmitry V Kurochkin
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, USA
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44
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Fazio B, Pieruccini M, Vasi C. A Mean Field Analysis of the O−H Stretching Raman Spectra in Methanol/Carbon Tetrachloride Mixtures. J Phys Chem B 2005; 109:16075-80. [PMID: 16853042 DOI: 10.1021/jp052587f] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The O-H stretching region of the Raman spectra obtained from methanol/carbon tetrachloride mixtures of different compositions is analyzed. The various components of the spectra associated with methanol molecules with different H-binding states (i.e., non-H-bonded, chain-end, and doubly bonded) are quantitatively related with the alcohol cluster distribution derived by means of a simple lattice model. This comparison allows for the estimate of the mean overall hydrogen bonding energy by means of a best fitting procedure on the Raman data obtained at low-to-moderate alcohol contents; the solvation energy contribution of carbon tetrachloride is then also included. The result (approximately 3 kcal/mol) is found to be in agreement with the estimates from calorimetric and dielectric measurements.
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Affiliation(s)
- B Fazio
- CNR, Istituto per i Processi Chimico-Fisici Sez. Messina, Via La Farina 237, I-98123 Messina, Italy
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45
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Piletic IR, Tan HS, Fayer MD. Dynamics of Nanoscopic Water: Vibrational Echo and Infrared Pump−Probe Studies of Reverse Micelles. J Phys Chem B 2005; 109:21273-84. [PMID: 16853758 DOI: 10.1021/jp051837p] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The dynamics of water in nanoscopic pools 1.7-4.0 nm in diameter in AOT reverse micelles were studied with ultrafast infrared spectrally resolved stimulated vibrational echo and pump-probe spectroscopies. The experiments were conducted on the OD hydroxyl stretch of low-concentration HOD in the H2O, providing a direct examination of the hydrogen-bond network dynamics. Pump-probe experiments show that the vibrational lifetime of the OD stretch mode increases as the size of the reverse micelle decreases. These experiments are also sensitive to hydrogen-bond dissociation and reformation dynamics, which are observed to change with reverse micelle size. Spectrally resolved vibrational echo data were obtained at several frequencies. The vibrational echo data are compared to data taken on bulk water and on a 6 M NaCl solution, which is used to examine the role of ionic strength on the water dynamics in reverse micelles. Two types of vibrational echo measurements are presented: the vibrational echo decays and the vibrational echo peak shifts. As the water nanopool size decreases, the vibrational echo decays become slower. Even the largest nanopool (4 nm, approximately 1000 water molecules) has dynamics that are substantially slower than bulk water. It is demonstrated that the slow dynamics in the reverse micelle water nanopools are a result of confinement rather than ionic strength. The data are fit using time-dependent diagrammatic perturbation theory to obtain the frequency-frequency correlation function (FFCF) for each reverse micelle. The results are compared to the FFCF of water and show that the largest differences are in the slowest time scale dynamics. In bulk water, the slowest time scale dynamics are caused by hydrogen-bond network equilibration, i.e., the making and breaking of hydrogen bonds. For the smallest nanopools, the longest time scale component of the water dynamics is approximately 10 times longer than the dynamics in bulk water. The vibrational echo data for the smallest reverse micelle displays a dependence on the detection wavelength, which may indicate that multiple ensembles of water molecules are being observed.
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Affiliation(s)
- Ivan R Piletic
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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46
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Bakker HJ, Gilijamse JJ, Lock AJ. Energy Transfer in Single Hydrogen-Bonded Water Molecules. Chemphyschem 2005; 6:1146-56. [PMID: 15887193 DOI: 10.1002/cphc.200400606] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We study the structure and dynamics of hydrogen-bonded complexes of H2O/HDO and acetone dissolved in carbon tetrachloride by probing the response of the O-H stretching vibrations with linear mid-infrared spectroscopy and femtosecond mid-infrared pump-probe spectroscopy. We find that the hydrogen bonds in these complexes break and reform with a characteristic time scale of approximately 1 ps. These hydrogen-bond dynamics are observed to play an important role in the equilibration of vibrational energy over the two O-H groups of the H2O molecule. For both H2O and HDO, the O-H stretching vibrational excitation relaxes with a time constant of 6.3+/-0.3 ps, and the molecular reorientation has a time constant of 6+/-1 ps.
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Affiliation(s)
- Huib J Bakker
- FOM Institute for Atomic and Molecular Physics, Kruislaan 407, 1098 SJ Amsterdam, The Netherlands.
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47
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Andanson JM, Soetens JC, Tassaing T, Besnard M. Hydrogen bonding in supercritical tert-butanol assessed by vibrational spectroscopies and molecular-dynamics simulations. J Chem Phys 2005; 122:174512. [PMID: 15910050 DOI: 10.1063/1.1886730] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have investigated the state of aggregation in supercritical tert-butanol (T = 523 K,0.05 < rho < 0.4 g cm(-3)) by means of vibrational spectroscopies (infrared and Raman) and molecular-dynamics (MD) simulations. A quantitative band shape analysis of the spectra associated with the OH stretching mode of tert-butanol has been done using activities computed by ab initio calculations on small clusters. This allows us to determine the degree of hydrogen bonding and populations of oligomers. These latter quantities have been derived from MD simulations and very consistent results are found with experiments. These results show that hydrogen bond still exist in supercritical tert-butanol and that the fluid mainly consists of oligomers smaller than tetramers.
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Affiliation(s)
- J-M Andanson
- Laboratoire de Physico-Chimie Moléculaire, Unité Mixte de Recherche (UMR) Centre National de la Recherche Scientifique (CNRS)-Université Bordeaux 1 no 5803.351, Cours de la Libération, Talence, France
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48
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Gilijamse JJ, Lock AJ, Bakker HJ. Dynamics of confined water molecules. Proc Natl Acad Sci U S A 2005; 102:3202-7. [PMID: 15722413 PMCID: PMC552901 DOI: 10.1073/pnas.0404916102] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We present femtosecond midinfrared pump-probe measurements of the molecular motion and energy-transfer dynamics of a water molecule that is enclosed by acetone molecules. These confined water molecules show hydrogen-bond and orientational dynamics that are much slower than in bulk liquid water. This behavior is surprising because the hydrogen bonds to the C=O groups of the acetone molecules are weaker than the hydrogen bonds in bulk water. The energy transfer between the O-H groups of the confined water molecules has a time constant of 1.3 +/- 0.2 ps, which is >20 times slower than in bulk water. We find that this energy transfer is governed completely by the rate at which hydrogen bonds are broken and reformed, and we identify the short-lived molecular complex that forms the transition state of this process.
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Affiliation(s)
- J J Gilijamse
- Foundation for Fundamental Research on Matter (FOM) Institute for Atomic and Molecular Physics (AMOLF), Kruislaan 407, 1098 SJ, Amsterdam, The Netherlands.
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49
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Marincean S, Jackson JE. Quest for IR-Pumped Reactions in Dihydrogen-Bonded Complexes. J Phys Chem A 2004. [DOI: 10.1021/jp048626p] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Simona Marincean
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824
| | - James E. Jackson
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824
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50
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Kayano M, Ebata T, Yamada Y, Mikami N. Picosecond IR–UV pump–probe spectroscopic study of the dynamics of the vibrational relaxation of jet-cooled phenol. II. Intracluster vibrational energy redistribution of the OH stretching vibration of hydrogen-bonded clusters. J Chem Phys 2004; 120:7410-7. [PMID: 15267651 DOI: 10.1063/1.1668641] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
A picosecond time-resolved IR-UV pump-probe spectroscopic study has been carried out for investigating the intracluster vibrational energy redistribution (IVR) and subsequent dissociation of hydrogen-bonded clusters of phenol (C6H5OH) and partially deuterated phenol (C6D5OH, phenol-d5) with various solvent molecules. The H-bonded OH stretching vibration was pumped by a picosecond IR pulse, and the transient S1-S0 UV spectra from the pumped level as well as the redistributed levels were observed with a picosecond UV laser. Two types of hydrogen-bonded clusters were investigated with respect to the effect of the H-bonding strength on the energy flow process: the first is of a strong "sigma-type H-bond" such as phenol-(dimethyl ether)(n=1) and phenol dimer, and the second is phenol-(ethylene)(n=1) having a weak "pi-type H-bond." It was found that the population of the IR-pumped OH level exhibits a single-exponential decay, whose rate increases with the H-bond strength. On the other hand, the transient UV spectrum due to the redistributed levels showed a different time evolutions at different monitoring UV frequency. From an analysis of the time profiles of the transient UV spectra, the following three-step scheme has been proposed for describing the energy flow starting from the IVR of the initially excited H-bonded OH stretching level to the dissociation of the H bond. (1) The intramolecular vibrational energy redistribution takes place within the phenolic site, preparing a hot phenol. (2) The energy flows from the hot phenol to the intermolecular vibrational modes of the cluster. (3) Finally, the hydrogen bond dissociates. Among the three steps, the rate constant of the first step was strongly dependent on the H-bond strength, while the rate constants of the other two steps were almost independent of the H-bond strength. For the dissociation of the hydrogen bond, the observed rate constants were compared with those calculated by the Rice, Ramsperger, Kassel, and Marcus model. The result suggests that dissociation of the hydrogen bond takes place much faster than complete energy randomization within the clusters.
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Affiliation(s)
- Masakazu Kayano
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan
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