The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Naohiko Mikami - One of the best experts on this subject based on the ideXlab platform.
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Picosecond time-resolved study on the intramolecular Vibrational energy redistribution of NH Stretching Vibration of jet-cooled aniline and its isotopomer
Chemical Physics Letters, 2006Co-Authors: Yuji Yamada, Naohiko Mikami, Jun-ichi Okano, Takayuki EbataAbstract:Abstract The real time observation of intramolecular Vibrational energy redistribution has been carried out for the NH2 symmetric and asymmetric Stretching Vibrations of jet-cooled aniline-d0 and aniline-d5. In both molecules, the IVR process can be described by two-step tier model. It was found that the isotope substitution affects the IVR rate oppositely between the symmetric and asymmetric Vibrations. The observed results were compared with that of the OH Stretching Vibration of phenol, and it was concluded that out-of-plane Vibrational modes play important roles as the doorway state in the IVR of the NH2 stretches of aniline, while in-plane modes in phenol.
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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
Journal of Chemical Physics, 2004Co-Authors: Masakazu Kayano, Takayuki Ebata, Yuji Yamada, Naohiko MikamiAbstract: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 “σ-type H-bond” such as phenol-(dimethyl ether)n=1 and phenol dimer, and the second is phenol-(ethylene)n=1 having a weak “π-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...
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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
Journal of Chemical Physics, 2004Co-Authors: Masakazu Kayano, Takayuki Ebata, Yuji Yamada, Naohiko MikamiAbstract: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 “σ-type H-bond” such as phenol-(dimethyl ether)n=1 and phenol dimer, and the second is phenol-(ethylene)n=1 having a weak “π-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...
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photofragment detected ir spectroscopy pfdirs for the oh Stretching Vibration of the hydrogen bonded clusters in the s1 stateapplication to 2 naphthol b b h2o and ch3oh clusters
Journal of Physical Chemistry A, 2001Co-Authors: Yoshiteru Matsumoto, And Takayuki Ebata, Naohiko MikamiAbstract:IR spectra of the OH Stretching Vibrations of 2-naphthol-B (B = H2O and CH3OH) clusters in S1 have been measured by photofragment detected IR spectroscopy (PFDIRS). In this spectroscopy, a tunable IR light pulse excites the OH Stretching Vibration of the electronically excited 2-naphthol-B, which is prepared by a UV light pulse. The Vibrationally excited cluster immediately predissociates to generate a 2-naphthol fragment in S1. By monitoring the emission only from the 000 band of the fragment with a monochromator while scanning the IR frequency, a background free IR spectrum of the OH Stretching Vibration of the cluster in S1 has been successfully obtained. By comparing the IR spectra of the cluster in S1 with those of in S0, the effect of the electronic excitation on the frequency change of the OH Stretching Vibration in the cluster is discussed.
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infrared dissociation spectroscopy of the oh Stretching Vibration of phenol rare gas van der waals cluster ions
Chemical Physics Letters, 1994Co-Authors: Asuka Fujii, Takayuki Ebata, Takahiro Sawamura, Shigeki Tanabe, Naohiko MikamiAbstract:Abstract Infrared dissociation spectra of phenol—Ar and —Kr van der Waals cluster ions in supersonic free jets were observed in the absorption region of the OH Stretching Vibration. Both spectra showed the OH Stretching Vibration at 3535 ± 2 cm−1, indicating that the perturbation of the rare gases is small and the observed frequency represents that of the bare phenol ion. The Vibrational frequency of the phenol ion was found to be 122 cm− smaller than that of neutral phenol.
Takayuki Ebata - One of the best experts on this subject based on the ideXlab platform.
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Picosecond time-resolved study on the intramolecular Vibrational energy redistribution of NH Stretching Vibration of jet-cooled aniline and its isotopomer
Chemical Physics Letters, 2006Co-Authors: Yuji Yamada, Naohiko Mikami, Jun-ichi Okano, Takayuki EbataAbstract:Abstract The real time observation of intramolecular Vibrational energy redistribution has been carried out for the NH2 symmetric and asymmetric Stretching Vibrations of jet-cooled aniline-d0 and aniline-d5. In both molecules, the IVR process can be described by two-step tier model. It was found that the isotope substitution affects the IVR rate oppositely between the symmetric and asymmetric Vibrations. The observed results were compared with that of the OH Stretching Vibration of phenol, and it was concluded that out-of-plane Vibrational modes play important roles as the doorway state in the IVR of the NH2 stretches of aniline, while in-plane modes in phenol.
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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
Journal of Chemical Physics, 2004Co-Authors: Masakazu Kayano, Takayuki Ebata, Yuji Yamada, Naohiko MikamiAbstract: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 “σ-type H-bond” such as phenol-(dimethyl ether)n=1 and phenol dimer, and the second is phenol-(ethylene)n=1 having a weak “π-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...
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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
Journal of Chemical Physics, 2004Co-Authors: Masakazu Kayano, Takayuki Ebata, Yuji Yamada, Naohiko MikamiAbstract: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 “σ-type H-bond” such as phenol-(dimethyl ether)n=1 and phenol dimer, and the second is phenol-(ethylene)n=1 having a weak “π-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...
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infrared dissociation spectroscopy of the oh Stretching Vibration of phenol rare gas van der waals cluster ions
Chemical Physics Letters, 1994Co-Authors: Asuka Fujii, Takayuki Ebata, Takahiro Sawamura, Shigeki Tanabe, Naohiko MikamiAbstract:Abstract Infrared dissociation spectra of phenol—Ar and —Kr van der Waals cluster ions in supersonic free jets were observed in the absorption region of the OH Stretching Vibration. Both spectra showed the OH Stretching Vibration at 3535 ± 2 cm−1, indicating that the perturbation of the rare gases is small and the observed frequency represents that of the bare phenol ion. The Vibrational frequency of the phenol ion was found to be 122 cm− smaller than that of neutral phenol.
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Infrared dissociation spectroscopy of the OH Stretching Vibration of phenol—rare gas van der Waals cluster ions
Chemical Physics Letters, 1994Co-Authors: Asuka Fujii, Takayuki Ebata, Takahiro Sawamura, Shigeki Tanabe, Naohiko MikamiAbstract:Abstract Infrared dissociation spectra of phenol—Ar and —Kr van der Waals cluster ions in supersonic free jets were observed in the absorption region of the OH Stretching Vibration. Both spectra showed the OH Stretching Vibration at 3535 ± 2 cm−1, indicating that the perturbation of the rare gases is small and the observed frequency represents that of the bare phenol ion. The Vibrational frequency of the phenol ion was found to be 122 cm− smaller than that of neutral phenol.
Anatolij M Yaremko - One of the best experts on this subject based on the ideXlab platform.
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theory of the profiles of hydrogen Stretching infrared bands of hydrogen bonded solids fermi resonance effect and strong coupling between the high frequency hydrogen Stretching Vibration and low frequency phonons
Chemical Physics Letters, 1999Co-Authors: H Ratajczak, Anatolij M YaremkoAbstract:Abstract A theory is developed to describe the profiles of hydrogen Stretching infrared bands of hydrogen-bonded solids taking into account the anharmonic coupling between the high-frequency Stretching Vibration, ν (XH), and low-frequency lattice phonons as well as a Fermi resonance between states involving the ν (XH) Stretching and an overtone or combination of some internal modes. The theory was constructed in the framework of the extended molecular exciton Davydov approach.
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theory of profiles of hydrogen Stretching infrared bands of hydrogen bonded solids model of strong coupling between the high frequency hydrogen Stretching Vibration and low frequency phonons
Chemical Physics Letters, 1995Co-Authors: H Ratajczak, Anatolij M YaremkoAbstract:Abstract A theory is developed to describe a broad IR absorption which appears in the range of a high-frequency Stretching Vibration of the X-H group involved in the hydrogen bond in solids. The theory is based on the anharmonic coupling mechanism between the high-frequency hydrogen Stretching Vibration. ν (XH), and low-frequency lattice phonons. The theory was constructed in the framework of the molecular exciton Davydov approach. Model calculations show that the strong anharmonic couplings between the high-frequency ν (XH) and low lattice Vibration frequencies generate the broadness of the ν (XH) band.
Peter Vohringer - One of the best experts on this subject based on the ideXlab platform.
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femtosecond 2dir spectroscopy of the nitrile Stretching Vibration of thiocyanate anions in liquid to supercritical heavy water spectral diffusion and libration induced hydrogen bond dynamics
Physical Chemistry Chemical Physics, 2015Co-Authors: Denis Czurlok, Jorg Lindner, Michael Von Domaros, Martin Thomas, Jeannine Gleim, Barbara Kirchner, Peter VohringerAbstract:Femtosecond two-dimensional infrared (2DIR) spectroscopy was carried out to study the dynamics of Vibrational spectral diffusion of the nitrile Stretching Vibration of thiocyanate anions (S–CN−) dissolved in liquid-to-supercritical heavy water (D2O). The 2DIR line shapes were used to extract through a nodal slope analysis quantitative information about the correlation function for temporal fluctuations of the CN-Stretching frequency. The inverse nodal slope could be fitted phenomenologically by a simple double-exponential decay whose predominant component had a time constant ranging between 300 fs and 1 ps depending on the temperature. The temperature dependence is interpreted in terms of solvent structural fluctuations that are driven by the librational motions of the D2O molecules located in the first solvation shell of the anion. Complementary molecular dynamics simulations of the SCN−/D2O system indicate that the breaking and making of hydrogen-bonds between the terminal N-atom of the anion and the D2O molecules are induced by the same solvent-shell librational degrees of freedom that drive the Vibrational line broadening dynamics seen in the 2DIR experiment.
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energy relaxation versus spectral diffusion of the oh Stretching Vibration of hod in liquid to supercritical deuterated water
Journal of Chemical Physics, 2005Co-Authors: Dirk Schwarzer, Jorg Lindner, Peter VohringerAbstract:The dynamics of Vibrational energy relaxation (VER) of the OH-Stretching Vibration of HOD in liquid-to-supercritical heavy water is studied as a function of temperature and solvent density by femtosecond mid-infrared spectroscopy. Using the dielectric constant of the fluid both, the OH-Stretching absorption frequency and the VER rate, can be correlated phenomenologically with the average hydrogen-bond connectivity within the random D2O network. This correlation enables the identification of thermodynamic conditions under which spectral diffusion due to hydrogen-bond breakage/formation is much faster than VER.
H Ratajczak - One of the best experts on this subject based on the ideXlab platform.
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theory of the profiles of hydrogen Stretching infrared bands of hydrogen bonded solids fermi resonance effect and strong coupling between the high frequency hydrogen Stretching Vibration and low frequency phonons
Chemical Physics Letters, 1999Co-Authors: H Ratajczak, Anatolij M YaremkoAbstract:Abstract A theory is developed to describe the profiles of hydrogen Stretching infrared bands of hydrogen-bonded solids taking into account the anharmonic coupling between the high-frequency Stretching Vibration, ν (XH), and low-frequency lattice phonons as well as a Fermi resonance between states involving the ν (XH) Stretching and an overtone or combination of some internal modes. The theory was constructed in the framework of the extended molecular exciton Davydov approach.
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theory of profiles of hydrogen Stretching infrared bands of hydrogen bonded solids model of strong coupling between the high frequency hydrogen Stretching Vibration and low frequency phonons
Chemical Physics Letters, 1995Co-Authors: H Ratajczak, Anatolij M YaremkoAbstract:Abstract A theory is developed to describe a broad IR absorption which appears in the range of a high-frequency Stretching Vibration of the X-H group involved in the hydrogen bond in solids. The theory is based on the anharmonic coupling mechanism between the high-frequency hydrogen Stretching Vibration. ν (XH), and low-frequency lattice phonons. The theory was constructed in the framework of the molecular exciton Davydov approach. Model calculations show that the strong anharmonic couplings between the high-frequency ν (XH) and low lattice Vibration frequencies generate the broadness of the ν (XH) band.