Faculty Profiles - FUSHITANI, Mizuho

Papers - FUSHITANI, Mizuho

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Coherent phonons in the zone boundary region of solid Ar doped with Cl2 Reviewed

Mizuho Fushitani, Nikolaus Schwentner, Maike Schroeder, Oliver Kuehn

ULTRAFAST PHENOMENA XV Vol. 88 page： 618 - + 2007

Language：English Publishing type：Research paper (international conference proceedings) Publisher：SPRINGER-VERLAG BERLIN

We report on coherent zone-boundary phonons of solid Ar doped with Cl-2 in pump-probe spectra. Comparison with molecular dynamic simulation shows that specific motions of Ar atoms in the (100) plane are responsible for the observed oscillations.

Web of Science

Visualizing recurrently migrating hydrogen by few-cycle intense laser pulses Reviewed

Akiyoshi Hishikawa, Akitaka Matsudal, Mizuho Fushitani, Eiji J. Takahashi

XXV INTERNATIONAL CONFERENCE ON PHOTONIC, ELECTRONIC AND ATOMIC COLLISIONS Vol. 88 2007

Language：English Publishing type：Research paper (international conference proceedings) Publisher：IOP PUBLISHING LTD

Ultrafast hydrogen migration in deuterated acetylene dication (C(2)D(2)(2+)) is studied by the pump-probe Coulomb explosion imaging with few-cycle intense laser pulses (9 fs, 0.13 PW/cm(2), 800 nm). The temporal evolution of the momenta of the fragment ions produced by the three-body explosion, C(2)D(2)(3+) -> D(+) + C(+) + CD(+), shows that the migration proceeds in a recurrent manner: The deuterium atom first shifts from one carbon site to the other in a short time scale (similar to 90 fs), and then migrates back to the original carbon site by 280 fs, in competition with the molecular dissociation.

DOI： 10.1088/1742-6596/88/1/012056

Web of Science

Coherent phonons in the zone boundary region of solid Ar doped with Cl2

Mizuho Fushitani, Nikolaus Schwentner, Maike Schroeder, Oliver Kuehn

ULTRAFAST PHENOMENA XV Vol. 88 page： 618 - + 2007

Ultrafast dynamics of halogens in rare gas solids

G{\"u}hr, M., Bargheer, M., Fushitani, M., Kiljunen, T., Schwentner, N.

Physical Chemistry Chemical Physics Vol. 9 ( 7 ) page： 779 - 801 2007

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：ROYAL SOC CHEMISTRY

We perform time resolved pump-probe spectroscopy on small halogen molecules ClF, Cl-2, Br-2, and I-2 embedded in rare gas solids (RGS). We find that dissociation, angular depolarization, and the decoherence of the molecule is strongly influenced by the cage structure. The well ordered crystalline environment facilitates the modelling of the experimental angular distribution of the molecular axis after the collision with the rare gas cage. The observation of many subsequent vibrational wave packet oscillations allows the construction of anharmonic potentials and indicate a long vibrational coherence time. We control the vibrational wave packet revivals, thereby gaining information about the vibrational decoherence. The coherence times are remarkable larger when compared to the liquid or high pressure gas phase. This fact is attributed to the highly symmetric molecular environment of the RGS. The decoherence and energy relaxation data agree well with a perturbative model for moderate vibrational excitation and follow a classical model in the strong excitation limit. Furthermore, a wave packet interferometry scheme is applied to deduce electronic coherence times. The positions of those cage atoms, excited by the molecular electronic transitions are modulated by long living coherent phonons of the RGS, which we can probe via the molecular charge transfer states.

DOI： 10.1039/b609058n

Web of Science

Scopus

PubMed

Correlation between nuclear spin ratio of cyclic C3H2 and chemical evolution in TMC-1 cores

Morisawa Yusuke, Fushitani Mizuho, Kato Yoshiyasu, Hoshina Hiromichi, Simizu Zenzo, Watanabe Shiori, Miyamoto Yuki, Kasai Yasuko, Kawaguchi Kentarou, Momose Takamasa

ASTROPHYSICAL JOURNAL Vol. 642 ( 2 ) page： 954 - 965 2006.5

Correlation between nuclear spin ratio of cyclic C3H2 and chemical evolution in TMC-1 cores Reviewed

Yusuke Morisawa, Mizuho Fushitani, Yoshiyasu Kato, Hiromichi Hoshina, Zenzo Simizu, Shiori Watanabe, Yuki Miyamoto, Yasuko Kasai, Kentarou Kawaguchi, Takamasa Momose

ASTROPHYSICAL JOURNAL Vol. 642 ( 2 ) page： 954 - 965 2006.5

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

The ortho-to-para nuclear spin ratio of cyclopropenylidene ( cyclic C3H2) in TMC-1 cores was investigated using the 45 m radio telescope at Nobeyama Radio Observatory. We have observed four ortho lines (J(KaKc) = 2(12) - 1(01), 3(12) - 3(03), 3(21) - 3(12), and 3(30) - 3(21)) and four para lines (J(KaKc) 2(02) - 1(11), 2(11) - 2(02), 2(20) - 2(11), and 3(22) - 3(13)) of cyclic C3H2 in six cores in TMC-1. A statistical equilibrium analysis of the observed intensities revealed apparent correlation between the ortho-to-para ratio of cyclic C3H2 and chemical evolution of the molecular cloud; the ortho-to-para ratio in younger cores is less than 2, while that in older cores is close to the statistical ratio of 3. A simple chemical model calculation indicates that the correlation is ascribed to the conservation of nuclear spin angular momenta in chemical reactions relevant to the production, destruction, and reproduction of cyclic C3H2. Since cyclic C3H2 has been observed in a variety of sources, the ortho-to-para ratio of cyclic C3H2 may be a useful probe of chemical evolution of molecular clouds.

DOI： 10.1086/501041

Web of Science

Chemical reactions in quantum crystals Reviewed

T Momose, M Fushitani, H Hoshina

INTERNATIONAL REVIEWS IN PHYSICAL CHEMISTRY Vol. 24 ( 3-4 ) page： 533 - 552 2005.12

Language：English Publisher：TAYLOR & FRANCIS LTD

Solid parahydrogen, known as a quantum crystal, is a novel matrix for the study of physical and chemical processes of molecules at low temperatures by high-resolution infrared spectroscopy. Ro-vibrational motion of molecules embedded in solid parahydrogen is well quantized on account of the weak interaction in the crystal. In addition, molecules are almost free from the cage effect because of the softness of the quantum crystal, so that a variety of chemical reactions could be observed for molecules in solid parahydrogen at liquid He temperatures. In this article, we survey our recent studies on photodissociation of methyl radicals and subsequent reactions in solid parahydrogen, and discuss ( 1) the nuclear spin selection rule in chemical reactions and ( 2) pure tunnelling reactions obtained from the analysis of the present system.

DOI： 10.1080/01442350500444107

Web of Science

Search for CCH-, NCO-, and NCS- Negative Ions in Molecular Clouds Reviewed Open Access

Y Morisawa, H Hoshina, Y Kato, Z Simizu, S Kuma, N Sogoshi, M Fushitani, S Watanabe, Y Miyamoto, T Momose, Y Kasai, K Kawaguchi

PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN Vol. 57 ( 2 ) page： 325 - 334 2005.4

Language：English Publishing type：Research paper (scientific journal) Publisher：OXFORD UNIV PRESS

Despite several suggestions concerning the existence of negatively charged molecules and negative atomic ions in molecular clouds, few attempts have been made to search for negative ions in molecular clouds. In the present study, we extensively searched for three negative molecular ions (CCH-, NCO-, and NCS-) in a dark cloud, L134N, using the Nobeyama 45-m radio telescope. The three negative ions are molecules whose rotational constants have been reported based on laboratory experiments. After a long accumulation, a trace amount of an unidentified emission line was detected at a frequency close to the theoretical prediction of the J = 1-0 transition of CCH-. If this unidentified line is attributable to CCH-, the observed emission intensity would provide an estimation of the column density of CCH- in L134N to be 1.0 x 10(11) cm(-2), which corresponds to a fractional abundance of 5 x 10(-12) relative to hydrogen. However, our recent observation using the IRAM 30-m telescope did not reproduce the J = 1-0 signal, nor detect any trace of the J = 2-1 transition. Thus, the identification of CCH- in L134N is not yet confirmed. As for other ions, signals of neither NCO- nor NCS- were detected in L134N. Although we also searched for the three negative ions in a translucent cloud, CB228, and a star-forming region, SgrB2, no signals were detected. The upper limit abundances of the ions in these clouds are discussed limit abundances of the ions in these clouds are discussed.

DOI： 10.1093/pasj/57.2.325

Web of Science

Scopus

Other Link： http://orcid.org/0000-0002-0567-6881

Wavepacket interferometry and wavepacket dynamics in condensed phase Reviewed

M Bargheer, M Fushitani, M Guhr, N Schwentner

ULTRAFAST PHENOMENA XIV Vol. 79 page： 304 - 306 2005

Wavepacket interferometry and wavepacket dynamics in condensed phase

M Bargheer, M Fushitani, M Guhr, N Schwentner

ULTRAFAST PHENOMENA XIV Vol. 79 page： 304 - 306 2005

Tunneling chemical reactions in solid parahydrogen: Direct measurement of the rate constants of R+H-2 -> RH+H (R=CD3,CD2H,CDH2,CH3) at 5 K Reviewed Open Access

H Hoshina, M Fushitani, T Momose, T Shida

JOURNAL OF CHEMICAL PHYSICS Vol. 120 ( 8 ) page： 3706 - 3715 2004.2

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER INST PHYSICS

Tunneling chemical reactions between deuterated methyl radicals and the hydrogen molecule in a parahydrogen crystal have been studied by Fourier transform infrared spectroscopy. The tunneling rates of the reactions R+H-2-->RH+H (R=CD3,CD2H,CDH2) in the vibrational ground state were determined directly from the temporal change in the intensity of the rovibrational absorption bands of the reactants and products in each reaction in solid parahydrogen observed at 5 K. The tunneling rate of each reaction was found to differ definitely depending upon the degree of deuteration in the methyl radicals. The tunneling rates were determined to be 3.3x10(-6) s(-1), 2.0x10(-6) s(-1), and 1.0x10(-6) s(-1) for the systems of CD3, CD2H, and CDH2, respectively. Conversely, the tunneling reaction between a CH3 radical and the hydrogen molecule did not proceed within a week's time. The upper limit of the tunneling rate of the reaction of the CH3 radical was estimated to be 8x10(-8) s(-1). (C) 2004 American Institute of Physics.

DOI： 10.1063/1.1642582

Web of Science

PubMed

High-resolution spectroscopy and the analysis of ro-vibrational transitions of molecules in solid parahydrogen Reviewed

T Momose, H Hoshina, M Fushitani, H Katsuki

VIBRATIONAL SPECTROSCOPY Vol. 34 ( 1 ) page： 95 - 108 2004.1

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Solid parahydrogen provides a novel matrix for isolation spectroscopy of atoms and molecules. Ro-vibrational motion of molecules embedded in solid parahydrogen is well quantized on account of the weak interactions in the crystal and of the softness of the crystal being characteristic of quantum crystals. Most of the observed spectral linewidths are one or two orders of magnitude sharper than those observed in conventional rare gas matrices. The sharp linewidths make the parahydrogen crystal an excellent matrix for the study of ro-vibrational states and dynamics of dopant molecules in the condensed phase by high-resolution spectroscopy. In this article, we have summarized the most fundamental part of our study, that is, the theory of ro-vibrational states of dopant molecules in the crystal, which is necessary for the quantitative analysis of high-resolution infrared spectra. We also discuss what we have learned from the analysis of high-resolution infrared spectra in solid parahydrogen. These include perturbations to rotational motion of dopant molecules, reduction of rotational constants, vibrational dephasing and relaxation. Outstanding questions to be solved are also discussed herein. (C) 2003 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.vibspec.2003.06.001

Web of Science

A study on diffusion of H atoms in solid parahydrogen Reviewed Open Access

M. Fushitani, T. Momose

Low Temperature Physics Vol. 29 ( 9-10 ) page： 740 - 743 2003.9

Publishing type：Research paper (scientific journal)

Diffusion of hydrogen atoms in solid parahydrogen was investigated using high-resolution infrared spectroscopy. Hydrogen atoms were produced as by-products of a photoinduced reaction of nitric oxides embedded in solid parahydrogen. The diffusion of the hydrogen atoms is mainly terminated by the reaction H+NO→HNO. The diffusion rate determined from the increase of the intensity of rotation-vibration transitions of HNO molecules was found to be two orders of magnitude larger than that determined by the self-recombination reaction of H+H→H2 in pure parahydrogen crystals. © 2003 American Institute of Physics.

DOI： 10.1063/1.1614182

Web of Science

Scopus

Quantum property of solid hydrogen as revealed by high-resolution laser spectroscopy Reviewed Open Access

H. Katsuki, M. Fushitani, T. Momose

Low Temperature Physics Vol. 29 ( 9-10 ) page： 832 - 837 2003.9

Publishing type：Research paper (scientific journal)

Pure vibrational overtone transitions of solid parahydrogen are studied using high-resolution laser spectroscopy. Extremely narrow spectral linewidth (∼20MHz) allows us to observe rich spectral structure that originates in subtle intermolecular interactions in the crystal. It is found that anisotropy of the distribution of zero-point lattice vibration of hydrogen molecules perturbs the energy levels of the vibrationally excited states significantly. A large amplitude of zero-point lattice vibration, an intrinsic propoerty of quantum solids, is directly observed from the present high-resolution spectroscopy. The first observation of a pure vibrational overtone transition of solid orthodeuterium is also discussed. © 2003 American Institute of Physics.

DOI： 10.1063/1.1619353

Web of Science

Scopus

Stimulated stokes downconversion in liquid and solid parahydrogen Reviewed

B. J. McCall, A. J. Huneycutt, R. J. Saykally, C. M. Lindsay, T. Oka, M. Fushitani, Y. Miyamoto, T. Momose

Applied Physics Letters Vol. 82 ( 9 ) page： 1350 - 1352 2003.3

Publishing type：Research paper (scientific journal)

The results of investigations into the suitability of condensed-phase parahydrogen as a Raman-shifting medium for infrared cavity ringdown laser absorption spectroscopy were reported. The conversion of ∼10-ns pulses of 532-nm radiation into first-, second-, and third-order vibrational Stokes radiation in bulk liquid and solid parahydrogen after a single 11-cm pass was observed. It was found that the liquid H2 yields more efficient conversion than solid H2 with certain focal geometries, and in case of the solid, a collimated or loosely focused pump geometry was more efficient than a tight focus.

DOI： 10.1063/1.1556560

Web of Science

Scopus

Generation of infrared radiation by stimulated Raman scattering in para-hydrogen crystal at 5 K Reviewed

Mizuho Fushitani, Susumu Kuma, Yuuki Miyamoto, Hiroyuki Katsuki, Tomonari Wakabayashi, Takamasa Momose, Andrey F. Vilesov

Optics Letters Vol. 28 ( 1 ) page： 37 - 39 2003.1

Publishing type：Research paper (scientific journal)

We report the preliminary results of our experiments with stimulated Raman scattering in para-hydrogen crystal aimed at developing a continuously tunable laboratory laser source of mid-infrared radiation. With laser pulses at 532 nm, a conversion efficieney for the first Stokes beam of as much as 20% in the forward direction was observed through a single-pass, 5-cm-long crystal. Generation of mid-infrared pulses at 4.5 μm was achieved by use of the output of a near-infrared pulsed laser (1.6 μm, 3 ns), and an absorption spectrum of gaseous CD4 molecules was successfully recorded. These results suggest use of the solid para-hydrogen Raman shifter as a promising light source for mid-infrared spectroscopy. © 2003 Optical Society of America.

DOI： 10.1364/OL.28.000037

Scopus

Generation of infrared radiation by stimulated Raman scattering in para-hydrogen crystal at 5 K

Fushitani M, Kuma S, Miyamoto Y, Katsuki H, Wakabayashi T, Momose T, Vilesov AF

OPTICS LETTERS Vol. 28 ( 1 ) page： 37 - 39 2003.1

The P-2(1/2)<- P-2(3/2) transition of the iodine atom photoproduced from alkyl iodides in solid parahydrogen: detection of new absorptions

Fushitani M, Momose T, Shida T

CHEMICAL PHYSICS LETTERS Vol. 356 ( 3-4 ) page： 375 - 382 2002.4

The <sup>2</sup>P<inf>1/2</inf> ← <sup>2</sup>P<inf>3/2</inf> transition of the iodine atom photoproduced from alkyl iodides in solid parahydrogen: Detection of new absorptions Reviewed

Mizuho Fushitani, Takamasa Momose, Tadamasa Shida

Chemical Physics Letters Vol. 356 ( 3-4 ) page： 375 - 382 2002.4

Publishing type：Research paper (scientific journal)

Alkyl iodides were photolyzed in solid parahydrogen at about 5 K. The first photolysis with 253.7 nm photons yielded two products by reactions, RI + hv (253.7 nm) → Rfree + ·Ifree and (R·-·I), the latter being a complex between the radical R· and the iodine atom ·I. Subsequent photolysis with 193 nm photons activated the radical moiety in both products to induce a reaction, R· + H2 + hv (193 nm) → RH + ·H, which gave the products RHfree and (RH-·I). The radical R· and the alkane RH were characterized by the mid-IR absorption while the iodine atoms in ·Ifree and (R·-·I) and (RH-·I) were identified by the near IR absorption of the magnetic dipole transition of the atom. © 2002 Published by Elsevier Science B.V.

DOI： 10.1016/S0009-2614(02)00354-8

Scopus

UV-photolysis of HI⋯CO<inf>2</inf> complexes in solid parahydrogen: Formation of CO and H<inf>2</inf>O Reviewed

Mizuho Fushitani, Tadamasa Shida, Takamasa Momose, Markku Räsänen

Journal of Physical Chemistry A Vol. 104 ( 16 ) page： 3635 - 3641 2000.4

Publishing type：Research paper (scientific journal)

The photochemistry of (HI)m⋯(CO2)n (m, n = 1,2, ...) complexes trapped in solid parahydrogen was studied by Fourier transform infrared absorption spectroscopy. Photolysis of the HI in the HI⋯(CO2)n complexes results in the generation of carbon monoxide and water molecules along with iodine atoms. Analysis of the observed spectra leads to the conclusion that the energetic hydrogen atom produced by the photolysis of HI initiates the reaction with one of the CCh molecules in the complexes as H + CO2 → OH + CO, which is followed by the secondary reaction of OH radicals with the matrix hydrogen as OH + H2 → H2O + H. These four-atom reactions are of practical importance in combustion processes as well as of theoretical importance in fundamental chemical dynamics. The result of the present study shows the usefulness of the parahydrogen matrix for fundamental study of photochemistry with the use of weakly bound complexes. © 2000 American Chemical Society.

DOI： 10.1021/jp9938462

Scopus

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Papers - FUSHITANI, Mizuho