Article
Chemistry, Multidisciplinary
Yang Luo, Alberto Martin-Jimenez, Rico Gutzler, Manish Garg, Klaus Kern
Summary: Tip-enhanced Raman spectroscopy (TERS) allows for the tracing of vibrational fingerprints of molecules and low-dimensional materials with subnanometer resolution. The localization of light in the plasmonic nanocavity of the STM enables high spatial resolution in STM-TERS. However, the temporal resolution is currently limited. In this study, stable TERS measurements were demonstrated from subphthalocyanine (SubPc) molecules excited by 500 fs long laser pulses in a low-temperature (LT) ultrahigh-vacuum (UHV) STM. The intensity of the TERS signal scales linearly with the increasing flux of the laser pulses and exponentially with the decreasing gap-size of the plasmonic nanocavity. Furthermore, the characteristic features of TERS excited with ultrashort pulses were compared with those excited with a continuous-wave (CW) laser.
Article
Spectroscopy
Vitaly Korepanov, Chun-Chieh Yu, Hiro-o Hamaguchi
Summary: In this study, the hyper-Raman spectra of liquid water were measured and the temperature-dependent spectra components were obtained through analysis. The results indicate that structured and non-structured hydrogen-bonded water coexist in thermal equilibrium in ambient liquid water.
JOURNAL OF RAMAN SPECTROSCOPY
(2022)
Article
Biochemistry & Molecular Biology
Yasuhiro Miwa, Tomoki Nagahama, Harumi Sato, Atsushi Tani, Kei Takeya
Summary: This passage introduces the attraction of semi-clathrate hydrates as heat storage materials and suggests that the variation of equilibrium temperatures is related to intermolecular and/or interionic interaction. By using low-frequency Raman spectroscopy, the correlation between Raman peak positions and equilibrium temperatures is observed. This observation is a valuable tool for studying equilibrium temperatures in semi-clathrate hydrates.
Article
Spectroscopy
Ankit Raj, Chihiro Kato, Henryk A. Witek, Hiro-o Hamaguchi
Summary: The article presents a multistep procedure for calibrating the sensitivity of Raman spectrometers, which was tested and proven effective in improving the accuracy of relative Raman intensities. The additional correction derived from Raman spectral intensities appears to be an important novel step towards the standardization of Raman spectroscopy.
JOURNAL OF RAMAN SPECTROSCOPY
(2021)
Article
Materials Science, Ceramics
Nektarios K. Nasikas, Angelos G. Kalampounias
Summary: By utilizing a nonconventional melting technique, researchers synthesized a series of calcium aluminate glasses and investigated the relationship between the low-frequency spectral changes and elastic properties. The study revealed a systematic dependence of the Boson Peak frequency on the CaO content, which is correlated with the elastic properties.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2022)
Article
Pharmacology & Pharmacy
Peter I. I. I. J. G. Remoto, Karlis Berzins, Sara J. Fraser-Miller, Timothy M. Korter, Thomas Rades, Jukka Rantanen, Keith C. Gordon
Summary: The solid-state landscape of carbamazepine during dehydration was investigated using both low- (-300 to -15, 15 to 300 cm(-1)) and mid- (300 to 1800 cm(-1)) frequency Raman spectroscopy. Density functional theory with periodic boundary conditions was employed to characterize the carbamazepine dihydrate and different forms, which showed good agreement with experimental Raman spectra. The dehydration process of carbamazepine dihydrate at various temperatures (40, 45, 50, 55, and 60 ?) was explored using principal component analysis and multivariate curve resolution, revealing different transformation pathways of solid-state forms. Low-frequency Raman spectroscopy was found to effectively detect the rapid growth and subsequent decline of carbamazepine form IV, which was not as well observed by mid-frequency Raman spectroscopy. These findings highlight the potential benefits of low-frequency Raman spectroscopy in pharmaceutical process monitoring and control.
Article
Medicine, Research & Experimental
Chima Robert, Sara J. Fraser-Miller, Karlis Berzins, Peter O. Okeyo, Jukka Rantanen, Thomas Rades, Keith C. Gordon
Summary: The study investigates the detection of solid-state forms of pharmaceutical compounds and the in situ isothermal dehydration process using low-frequency Raman (LFR) spectroscopy. Principal component analysis and multivariate curve resolution were used to analyze the data and reveal the differences in vibration properties between different frequency regions. Computational simulations were in agreement with experimental results, elucidating the origin of various spectral features.
MOLECULAR PHARMACEUTICS
(2021)
Article
Physics, Applied
Li Wang, Zhen Xie, Shenlong Jiang, Qun Zhang, Yi Luo
Summary: Spatial mapping of low-frequency Raman modes in twisted bilayer graphene (tBLG) via micro-Raman spectroscopy (mRS) imaging reveals a region-dependent, highly localized awakening of the combination C+ZO' mode. Analyses based on Raman G- and 2D-mode frequencies, G-band splitting, and polarization-dependent Raman intensity distributions show a sensitive correlation between the mode activation and mechanical strain distributions.
APPLIED PHYSICS LETTERS
(2022)
Article
Medicine, Research & Experimental
Karlis Berzins, Joseph I. Mapley, Keith C. Gordon, Sara J. Fraser-Miller
Summary: This work explores the potential use of spatially offset low-frequency anti-Stokes Raman spectroscopy (SOLFARS) to detect subsurface composition below an emissive surface. The study found that the commonly used midfrequency region (300-1800 cm-1) is superior for quantifying coating thickness, while a combined Stokes and anti-Stokes low-frequency region is better for quantifying underlying crystalline materials. For exploring subsurface composition, the anti-Stokes LFR spectral window performs best.
MOLECULAR PHARMACEUTICS
(2022)
Article
Spectroscopy
Vlasta Mohacek-Grosev, Kresimir Furic, Vedran Vujnovic
Summary: This study presents new Raman data on the aggregation of H2O and D20 water in an argon matrix, and performs molecular dynamics simulations. The results show that water molecules form dimers, trimers, tetramers, and pentamers, and the assignment of OH stretching vibrations is confirmed by comparing with theoretical calculations and previous experiments. The study also reveals a shift in the Raman bands of water molecules in the argon matrix compared to free water clusters.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2022)
Article
Multidisciplinary Sciences
Andreij C. Gadelha, Douglas A. A. Ohlberg, Cassiano Rabelo, Eliel G. S. Neto, Thiago L. Vasconcelos, Joao L. Campos, Jessica S. Lemos, Vinicius Ornelas, Daniel Miranda, Rafael Nadas, Fabiano C. Santana, Kenji Watanabe, Takashi Taniguchi, Benoit van Troeye, Michael Lamparski, Vincent Meunier, Viet-Hung Nguyen, Dawid Paszko, Jean-Christophe Charlier, Leonardo C. Campos, Luiz G. Cancado, Gilberto Medeiros-Ribeiro, Ado Jorio
Summary: The twisted bilayer graphene undergoes self-organized lattice reconstruction, resulting in the formation of a superlattice that modulates vibrational and electronic structures, leading to phenomena such as strong correlations and superconductivity. Although experimental techniques and theoretical models face challenges in observing and describing these effects, nano-Raman spectroscopy can localize some vibrational modes and provide insights into the effects of electron-phonon coupling on the material properties.
Review
Pharmacology & Pharmacy
Karlis Berzins, Sara J. Fraser-Miller, Keith C. Gordon
Summary: Low-frequency Raman (LFR) spectroscopy is a technique that probes vibrational modes related to long-range order and crystallinity in solids, providing unique information about their properties. Recent advancements in instrumentation and data analysis have overcome previous limitations and led to a surge in popularity of LFR spectroscopy with applications in various research areas, particularly pharmaceutical analysis. This mini-review article comprehensively summarizes established and exciting new LFR applications, discussing aspects of theory, instrumentation, and data analysis including the use of chemometric and computational techniques.
INTERNATIONAL JOURNAL OF PHARMACEUTICS
(2021)
Review
Chemistry, Physical
Katsuyoshi Ikeda
Summary: SERS spectroscopy is a versatile tool for studying surface phenomena under electrochemical or photoelectrochemical conditions. The recent advancements in optical filter technology have extended the frequency range covered by a conventional single-stage Raman spectrometer into the terahertz or far-infrared range. The frequency-extended SERS provides complementary mass and chemical information simultaneously, allowing for a better understanding of heterogeneous reactions at the molecular scale.
CURRENT OPINION IN ELECTROCHEMISTRY
(2023)
Article
Polymer Science
Yumiko Yamamoto, Hiromichi Hoshina, Harumi Sato
Summary: The differences in intermolecular interactions and flexibility between PET and PBT were studied through spectroscopy and chemical calculations. PBT shows intermolecular hydrogen bonding, while PET does not, leading to differences in thermal behavior and vibrational modes. These differences are attributed to the number of CH2 groups and potential intermolecular hydrogen bonding.
Article
Spectroscopy
Shuo Zhang, Hongsheng Jia, Mingxing Song, He Shen, Li Dongfei, Li Haibo
Summary: The low-temperature studies of liquid CH3CN were conducted using Raman spectral measurements, revealing structural phase transitions at -50 and -60 degrees C. Fermi resonance parameters were calculated and found to show discontinuities at the same temperatures as observed in Raman shifts of CH3CN. This suggests that Fermi resonance parameters can be used as an indicator for structural phase transitions in CH3CN under low temperature.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2021)
Article
Engineering, Biomedical
Xin-Chun Huang, Li-Bang Wu, Jen-Fang Hsu, Shinsuke Shigeto, Hsin-Yun Hsu
ACTA BIOMATERIALIA
(2015)
Article
Chemistry, Physical
Hong-Kai Chen, Nitin Srivastava, Satyen Saha, Shinsuke Shigeto
Article
Chemistry, Physical
Sudhakar Narra, Chih-Chun Chung, Eric Wei-Guang Diau, Shinsuke Shigeto
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2016)
Article
Chemistry, Physical
Shogo Toda, Shinsuke Shigeto
JOURNAL OF PHYSICAL CHEMISTRY B
(2017)
Article
Chemistry, Physical
Shinsuke Shigeto, Chun-Fu Chang, Hirotsugu Hiramatsu
JOURNAL OF PHYSICAL CHEMISTRY B
(2017)
Article
Chemistry, Physical
Shogo Toda, Shinsuke Shigeto
JOURNAL OF PHYSICAL CHEMISTRY C
(2018)
Article
Spectroscopy
Ami Matsuda, Naoko Sakaguchi, Shinsuke Shigeto
JOURNAL OF RAMAN SPECTROSCOPY
(2019)
Article
Chemistry, Analytical
Mitsuru Yasuda, Norio Takeshita, Shinsuke Shigeto
ANALYTICAL CHEMISTRY
(2019)
Article
Chemistry, Physical
Shogo Toda, Naoya Yanagita, Effat Jokar, Eric Wei-Guang Diau, Shinsuke Shigeto
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2020)
Article
Chemistry, Multidisciplinary
Shogo Toda, Ryan Clark, Tom Welton, Shinsuke Shigeto
Summary: Electric potential induces ordering of ILs near the IL-electrode interface, resulting in uniform intensity changes in Raman difference spectra. This effect contrasts sharply with previous observations on molecular liquids. The experimental results reveal a ordering length scale in ILs of tens to hundreds of nanometers, extending beyond the electrical double layer but not reaching a micrometer scale.
Article
Multidisciplinary Sciences
Nanako Kanno, Shingo Kato, Moriya Ohkuma, Motomu Matsui, Wataru Iwasaki, Shinsuke Shigeto
Summary: Utilizing a combination of machine learning and single-cell Raman microspectroscopy allows for accurate classification of phylogenetically diverse prokaryotes, shedding light on microbial dark matter. The presence of carotenoids and membrane lipid structure play key roles in distinguishing prokaryotic species, with unique Raman markers identified for an ammonia-oxidizing archaeon.
Article
Chemistry, Physical
Shogo Toda, Eric Wei-Guang Diau, Shinsuke Shigeto
Summary: Recent developments in 2D Ruddlesden-Popper perovskites have opened up a new phase in optoelectronics due to their promising physical, chemical, and optical properties. In this study, the grain orientation of thin films of the horizontal 2D perovskite BA(2)PbI(4) was successfully mapped using lowfrequency polarized Raman microspectroscopy, providing valuable insights into crystallographic information and properties of 2D perovskite thin films in general.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Physical
Risa Sasaki, Shogo Toda, Takaiku Sakamoto, Eiji Sakuradani, Shinsuke Shigeto
Summary: This study used fluorescent resonance Raman and multiplex coherent anti-Stokes Raman scattering microscopy to observe and characterize lipids and carotenoids accumulated in single living Aurantiochytrium limacinum cells. The results revealed that as the culture time increased, the lipid amount increased by a factor of about 7, while the carotenoid amount did not change significantly.
JOURNAL OF PHYSICAL CHEMISTRY B
(2023)
Article
Chemistry, Physical
Takayuki Hiraoka, Shinsuke Shigeto
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2020)