Article
Multidisciplinary Sciences
Deepak Ojha, Thomas D. Kuehne
Summary: In this study, a simple recipe based on narrowband IR pump and broadband vSFG probe technique was used to computationally obtain the two-dimensional vSFG spectrum of water molecules at the air-water interface. The study demonstrated that the vibrational spectral dynamics of the free OH bond is faster than that of the bonded OH mode at the interface.
SCIENTIFIC REPORTS
(2021)
Article
Optics
Karolis Madeikis, Robertas Kananavicius, Rokas Danilevicius, Audrius Zaukevicius, Regimantas Januskevicius, Andrejus Michailovas
Summary: This work presents the development of a femtosecond tunable mid-IR radiation source for a compact broadband high-resolution SFG spectroscopy system, achieving >5(X)cm(-1) bandwidth widely tunable microjoule level pulses in the mid-IR spectral region. The developed SFG spectrometer demonstrates a unique combination of parameters with excellent spectral resolution and fast simultaneous acquisition of broadband spectra.
Article
Chemistry, Physical
Tong Zhang, Zhi-Chao Huangfu, Yuqin Qian, Zhou Lu, Hong Gao, Yi Rao
Summary: In this work, broadband heterodyne detection was used to study the frequency-dependent spectral phases in interfacial electronic spectroscopy. It was found that the often-used Au thin film is not a suitable reference for frequency-dependent phases.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Physical
Preeti Gahtori, Srinivasa Rao Varanasi, Ravindra Pandey
Summary: This paper investigates the spectral responses of interfacial water molecules due to interactions of differently charged gold nanoparticles with model cell membranes using vibrational sum frequency generation and molecular dynamics simulation techniques. The results show significant changes in the orientation and structure of interfacial water molecules in the presence of charged gold nanoparticles, providing valuable insights for designing and optimizing delivery systems for biomedical applications.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Multidisciplinary
Verena Pramhaas, Holger Unterhalt, Hans-Joachim Freund, Guenther Rupprechter
Summary: The surface structure and shape of oxide-supported metal nanoparticles can be determined using polarization-dependent sum-frequency-generation (SFG) spectroscopy. This technique reveals the average surface structure and shape of the nanoparticles and can be used to monitor particle restructuring in situ. It has the potential to be a valuable tool for operando catalysis.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Hao Lu, Luca Bellucci, Shumei Sun, Daizong Qi, Marta Rosa, Ruediger Berger, Stefano Corni, Mischa Bonn
Summary: The assembly mechanism of Aβ peptides at hydrophobic interfaces depends on the pH, with acidic conditions promoting the formation of extended β-strand fibrils and facilitating macroscopic assembly.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Azhad U. Chowdhury, Dongsook Chang, Yuewen Xu, Kunlun Hong, Bobby G. Sumpter, Jan-Michael Y. Carrillo, Benjamin Doughty
Summary: This study utilized SFG technology and molecular dynamic simulations to reveal characteristics of polymer interfaces, including the ordering and orientations of key functional groups. Results show that different architectures of polymers exhibit differences in surface orientation, but molecular weight or architecture does not strongly impact surface properties.
Article
Chemistry, Physical
Laura Vietze, Ellen H. G. Backus, Mischa Bonn, Maksim Grechko
Summary: In condensed molecular matter, low-frequency modes play a crucial role in determining thermodynamic parameters and functions, and can be measured directly using two-dimensional terahertz-infrared-visible spectroscopy. However, interference between signals from different excitation pathways may complicate the analysis of spectra.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Yusef R. Farah, Amber T. Krummel
Summary: The electronic structure of the N3/TiO2 interface has a direct impact on the performance of dye sensitized solar cells. This study found that significant changes occur in the dye's orientation at pH ≤ 2.0, resulting in a change in the interfacial electronic structure that hinders electron transfer.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Lu Lin, Zening Liu, Uvinduni I. Premadasa, Tianyu Li, Ying-Zhong Ma, Robert L. Sacci, John Katsaras, Kunlun Hong, C. Patrick Collier, Jan-Michael Y. Carrillo, Benjamin Doughty
Summary: This study discovers that specific cation effects can modulate the assemblies of hydrophobic tails in cationic amphiphiles at liquid/liquid interfaces. It is demonstrated that small cations, such as Li+, can bind to the oxygen atoms in the hydrophobic tails and pin them to the interface, resulting in a kinked conformation. This finding not only provides a method for controlling molecular assembly at liquid/liquid interfaces, but also offers insights for applications such as Li+ separation in soft-matter electronics.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Multidisciplinary Sciences
Gang-Hua Deng, Yuqin Qian, Tong Zhang, Jian Han, Hanning Chen, Yi Rao
Summary: Interactions of electronic and vibrational degrees of freedom play a crucial role in understanding excited-state relaxation pathways of molecular systems at interfaces and surfaces. The development of interface-specific two-dimensional electronic-vibrational sum frequency generation (2D-EVSFG) spectroscopy reveals strong vibronic couplings and the relaxation process in photoexcited interface-active molecules. Time-dependent experiments show that the relaxation of the locally excited state is strongly coupled with specific high-frequency modes, leading to the transition to a lower excited state.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Chemistry, Multidisciplinary
Chengcheng Zhang, Jinpeng Gao, Jeanne Hankett, Prabodh Varanasi, Charles O. Kerobo, Shouxun Zhao, Zhan Chen
Summary: The study highlights the significant impact of sizing solutions on the wettability and interfacial adhesion of composites. Surface-sensitive sum frequency generation (SFG) spectroscopy offers valuable insights into the complex structures of sizing solutions at solid-liquid interfaces, enabling a more accurate understanding of the structure-wettability relationship. This detailed understanding of interactions between sizing agents and substrates promotes informed and optimized selections of sizing formulations.
Article
Multidisciplinary Sciences
Angelo Montenegro, Chayan Dutta, Muhammet Mammetkuliev, Haotian Shi, Bingya Hou, Dhritiman Bhattacharyya, Bofan Zhao, Stephen B. Cronin, Alexander V. Benderskii
Summary: This experimental study reveals that the dielectric response of interfacial water may deviate from linear response, challenging the traditional view of treating interfacial water as a simple dielectric medium. Vibrational sum-frequency generation spectra show significant asymmetry for negative versus neutral/positive electrode charge conditions.
Article
Chemistry, Multidisciplinary
Zhaohui Xu, Yinyu Zhang, Yeping Wu, Xiaolin Lu
Summary: In this study, the interfacial bonding formation between an epoxy adhesive and sapphire or silica substrates upon curing and post-curing steps was traced using SFG vibrational spectroscopy. The study revealed the formation of interfacial chemical bonding and enhanced ordering of sapphire surface OH groups. Additionally, it showed that the silica surface is relatively less hydrophilic compared to the sapphire surface, as evidenced by weak vibrational signals.
Article
Chemistry, Multidisciplinary
Yongsheng Luo, Ai-Ping Pang, Xiaolin Lu
Summary: The development of micro/nanofluidic techniques has sparked interest in dynamic shear flow at liquid-solid interfaces. Recent research has shown that the slip of fluids relative to solid walls can be influenced by the liquid flow, but the prediction and control of flow in the boundary layer remains challenging. This Perspective summarizes recent advances in understanding the microscopic structures at liquid-solid interfaces under shear flow, with a focus on the application of sum frequency generation vibrational spectroscopy. The authors discuss possible approaches for controlling interfacial slip and highlight current challenges and opportunities.
Article
Chemistry, Multidisciplinary
Johannes Hunger, Jan Schaefer, Patrick Ober, Takakazu Seki, Yongkang Wang, Leon Praedel, Yuki Nagata, Mischa Bonn, Douwe Jan Bonthuis, Ellen H. G. Backus
Summary: Understanding the collective behavior of ions at charged surfaces is crucial for geological and electrochemical processes. In this study, sum-frequency generation (SFG) spectroscopy was used to investigate the symmetry-breaking of water molecules at a charged silica surface in contact with different alkaline metal chloride solutions. The results demonstrate that the water response varies with the cation, with LiCl showing a significantly enhanced SFG response compared to CsCl. Further analysis indicates that the effect of different salts on the optical response is indirectly mediated by the reorganization of interfacial water.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Multidisciplinary Sciences
Kuo-Yang Chiang, Takakazu Seki, Chun-Chieh Yu, Tatsuhiko Ohto, Johannes Hunger, Mischa Bonn, Yuki Nagata
Summary: The dielectric properties of interfacial water on subnanometer length scales have been studied using surface-specific sum-frequency generation spectra. Experimental and simulated results reveal a drastic change in the interfacial dielectric constant in the subnanometer interfacial water region, leading to the formation of an electric triple-layer at charged planar interfaces.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Editorial Material
Chemistry, Multidisciplinary
Yuki Nagata, Mischa Bonn
ACS CENTRAL SCIENCE
(2022)
Article
Chemistry, Multidisciplinary
Yongkang Wang, Takakazu Seki, Xuan Liu, Xiaoqing Yu, Chun-Chieh Yu, Katrin F. Domke, Johannes Hunger, Marc T. M. Koper, Yunfei Chen, Yuki Nagata, Mischa Bonn
Summary: We used HD-SFG spectroscopy to directly probe the interfacial water at the graphene electrode supported on CaF2. The observed phase transition-like variations in the HD-SFG spectra were not due to the charging/discharging of graphene, but rather the CaF2 substrate through pseudocapacitive process. The potential-dependent spectra were similar to the pH-dependent spectra, indicating that the pseudocapacitive behavior was associated with a local pH change induced by water dissociation between CaF2 and graphene.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Xiaoqing Yu, Kuo-Yang Chiang, Chun-Chieh Yu, Mischa Bonn, Yuki Nagata
Summary: Insights into the microscopic structure of aqueous interfaces are important for understanding various processes on the water surface. The researchers used HD-SFG spectroscopy to probe these interfaces and showed the importance of correcting the measured spectra for local electromagnetic field effects. They compared different models to obtain an accurate representation of the interfacial water response and found that the Lorentz model provides a straightforward method for obtaining the molecular response in the hydrogen-bonded region.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Kazuki Inoue, Yair Litman, David M. Wilkins, Yuki Nagata, Masanari Okuno
Summary: The impact of vibrational coupling on water spectra is studied using hyper-Raman (HR) spectroscopy and machine learning. Isotopic dilution reduces the HR bandwidth, but the coupling effect is smaller compared to IR and Raman spectra. Machine learning HR spectra reveal that intermolecular coupling plays a major role in broadening the bandwidth, while intramolecular coupling has negligible impact, consistent with IR and Raman spectra. This study demonstrates the limited effect of intramolecular vibrations, independent of selection rules in vibrational spectroscopy.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Takakazu Seki, Chun-Chieh Yu, Kuo-Yang Chiang, Alessandro Greco, Xiaoqing Yu, Fumiki Matsumura, Mischa Bonn, Yuki Nagata
Summary: In typical aqueous systems, multiple ion species are co-solvated, and these ions at the water-air interface can have significant impacts on chemical reactivity, aerosol formation, climate, and water odor. Through sum-frequency generation spectroscopy, researchers have quantified the relative surface activity of two co-solvated ions and found that hydrophobic ions tend to be speciated to the water interface due to the presence of hydrophilic ions. The speciation of ions at electrolyte solution interfaces is determined by the solvation energy difference between the ions and the intrinsic surface propensity of ions.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Physical
Johannes Sutter, Constantin Haese, Robert Graf, Johannes Hunger
Summary: This study investigates the mechanism of proton transport in protic ionic liquids (PILs) using dielectric relaxation spectroscopy and nuclear magnetic resonance spectroscopy. The results demonstrate the sensitivity of protonation equilibria to the immediate environment of PILs and the influence of these equilibria on proton dynamics. Tuning the composition of PILs can be used to control the contribution of proton transport to charge transport.
JOURNAL OF MOLECULAR LIQUIDS
(2023)
Article
Chemistry, Physical
Tsung-Han Liu, Masanari Okuno
Summary: For the first time, hyper-Raman (HR) spectroscopy has been used to characterize the secondary structures of polypeptides, poly-l-lysine and poly-l-glutamic acid, in aqueous solutions. HR spectroscopy complements infrared (IR) and visible Raman spectroscopy by providing unique spectral features that allow the distinction of different conformations. The HR spectra exhibit similarities to UV resonance Raman (UVRR) spectra, indicating signal enhancement through electronic resonance effects. These findings suggest that HR spectroscopy can be a valuable tool for investigating the secondary structures of polypeptides in aqueous solutions, offering complementary information to existing vibrational spectroscopic methods.
JOURNAL OF PHYSICAL CHEMISTRY B
(2023)
Article
Chemistry, Physical
Pankaj Seliya, Mischa Bonn, Maksim Grechko
Summary: This study focuses on the interaction between quantum-mechanical systems and fluctuating thermal environments, providing insights into their coupling through a combined experimental and theoretical approach. The experimental part involves spectroscopy measurements to directly observe the coupling between quantum oscillators and low-frequency modes. The theoretical part introduces a mixed quantum-classical formalism to describe the sample response. This approach enables the quantitative and mode-specific analysis of coupled quantum and classical dynamics in complex chemical systems.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Yongkang Wang, Yuki Nagata, Mischa Bonn
Summary: Graphene, as a transparent two-dimensional conductive electrode, has brought new perspectives to electrochemical systems. The substrate plays a crucial role in determining the water organization and wetting behavior of graphene. Surface-specific spectroscopy study reveals that the charging of graphene is decoupled from the charging of its substrate.
FARADAY DISCUSSIONS
(2023)
Article
Engineering, Electrical & Electronic
Xuan Zhou, Fan Shi, Jiafeng Lu, Mengjun Xu, Mengdie Hou, Mischa Bonn, Xiaomin Liu, Xianglong Zeng
Summary: This paper proposes a method for producing femtosecond visible doughnut beams by integrating nonlinear frequency conversion and in-fiber mode conversion techniques. This method allows for dynamic manipulation of vector visible beams in optical fibers.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Chemistry, Multidisciplinary
Gabriele C. Sosso, Prerna Sudera, Anna T. Backes, Thomas F. Whale, Janine Froehlich-Nowoisky, Mischa Bonn, Angelos Michaelides, Ellen H. G. Backus
Summary: By conducting experiments and simulations, this study systematically investigates the ice-nucleating ability of cholesterol in both crystalline and disordered self-assembled monolayers. A sweet spot in terms of the surface coverage of the monolayers is identified, where cholesterol enhances the structural order of interfacial water molecules and maximizes its ability to nucleate ice.
