研究者詳細 - 宮本　祐樹

Simultaneous measurements of super-radiance at multiple wavelengths from helium excited states: I. Experiment 査読

Nakajima, K., Harries, J.R., Iwayama, H., Kuma, S., Miyamoto, Y., Nagasono, M., Ohae, C., Togashi, T., Yabashi, M., Shigemasa, E., Sasao, N.

Journal of the Physical Society of Japan 84 ( 5 ) 2015年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PHYSICAL SOC JAPAN

In this paper, we report the results of measurements of the intensities and delays of super-radiance decays from excited helium atoms at multiple wavelengths. The experiment was performed using extreme ultraviolet radiation produced by the free electron laser at the SPring-8 Compact SASE Source test accelerator facility as an excitation source. We observed super-radiant transitions on the 1s3p -> 1s2s (lambda = 502 nm), 1s3d -> 1s2p (lambda = 668 nm), and 1s3s -> 1s2p (lambda = 728 nm) transitions. The pulse energy of each transition and its delay time were measured as a function of the target helium gas density. Several interesting features of the data, some of which appear to contradict with the predictions of the simple two-level super-radiance theory, are pointed out.

DOI： 10.7566/JPSJ.84.054301

Low-lying electronic states in bismuth trimer Bi <inf>3</inf> As revealed by laser-induced NIR emission spectroscopy in solid Ne 査読

Wakabayashi, T., Wada, Y., Nakajima, K., Morisawa, Y., Kuma, S., Miyamoto, Y., Sasao, N., Yoshimura, M., Sato, T., Kawaguchi, K.

Journal of Physical Chemistry A 119 ( 11 ) 2644 - 2650 2015年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

Laser-induced near-infrared (NIR) emission spectra of neutral bismuth timer, Bi-3, embedded in solid neon matrixes at 3 K were recorded in a range 870-1670 nm. Using photoexcitation with low energy photons at 1064 nm, two emission band systems were newly identified by their origin bands at T-0 = 6600 and 8470 cm(-1). Accordingly, spectral assignment for three NIR emission band systems reported recently was partly revised for the one with its origin band at T-0 = 7755 cm(-1) and reconfirmed for the others at T-0 = 9625 and 11 395 cm(-1). Energy splitting by spin-orbit coupling between the pair of electronic energy levels in the ground state of bismuth trimer, Bi-3, both having a totally symmetric vibrational mode of frequency at omega"(e) = 150 cm(-1), was determined to be 1870 +/- 1.5 cm(-1). Transitions from the pair of electronically excited states, locating at T-0 = 8470 and 9625 cm(-1) above the ground state and separated by spin-orbit coupling of 1155 cm(-1), have relatively long decay constants of tau similar to 0.2 and similar to 0.1 ms, respectively.

DOI： 10.1021/jp509714f

Observation of coherent two-photon emission from the first vibrationally excited state of hydrogen molecules 査読

24aBG-11 EUV-FEL励起ヘリウム原子集団における多準位間超放射(I)実験

中嶋享, HARRIES James R., 岩山洋士, 久間晋, 宮本祐樹, 永園充, 大饗千彰, 富樫格, 繁政英治, 笹尾登

日本物理学会講演概要集 70 771 - 771 2015年

22aDF-11 SPAN(原子を用いたニュートリノ質量分光実験)のためのマクロコヒーレント増幅機構の詳細研究II

原秀明, 増田孝彦, 宮本祐樹, 中野逸夫, 笹尾登, 田中実, 植竹智, 吉見彰洋, 吉村浩司, 吉村太彦

日本物理学会講演概要集 70 86 - 86 2015年

24aBG-12 EUV-FEL励起ヘリウム原子集団における多準位間超放射(II)解析

大饗千彰, HARRIES James R., 岩山洋士, 久間晋, 宮本祐樹, 永園充, 中嶋享, 繁政英治, 若林知成, 笹尾登

日本物理学会講演概要集 70 772 - 772 2015年

22pAG-7 水素分子振動準位間のコヒーレント2光子放出III

植竹智, 原秀明, 増田孝彦, 宮本祐樹, 中野逸夫, 笹尾登, 田中実, 吉見彰洋, 吉村浩司, 吉村太彦

日本物理学会講演概要集 70 668 - 668 2015年

Miyamoto, Y., Hara, H., Kuma, S., Masuda, T., Nakano, I., Ohae, C., Sasao, N., Tanaka, M., Uetake, S., Yoshimi, A., Yoshimura, K., Yoshimura, M.

Progress of Theoretical and Experimental Physics 2014 ( 11 ) 2014年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：OXFORD UNIV PRESS INC

In this paper, we describe an experiment which was conducted to explore the macro-coherent amplification mechanism using a two-photon emission process from the first vibrationally excited state of the para-hydrogen molecule. Large coherence in the initial state was prepared by the adiabatic Raman method, and the lowest Stokes sideband was used as a trigger field. We observed coherent two-photon emission consistent with the expectation of the Maxwell-Bloch equation derived for the process, whose rate is larger by many orders of magnitude than that of spontaneous emission.

DOI： 10.1093/ptep/ptu152

Production of ba metastable state via superradiance 査読

Ohae, C., Fukumi, A., Kuma, S., Miyamoto, Y., Nakajima, K., Nakano, I., Nanjo, H., Sasao, N., Uetake, S., Wakabayashi, T., Yoshimi, A., Yoshimura, K., Yoshimura, M.

Journal of the Physical Society of Japan 83 ( 4 ) 2014年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：PHYSICAL SOC JAPAN

We describe in this paper a fast and efficient method of producing a high density of barium (Ba) atoms in the D-1(2) metastable state, which is a candidate initial state for a new class of cooperative and coherent optical process called paired superradiance (PSR). In the experiment, Ba atoms are excited first by laser light to the P-1(1) state and then brought to the desired state D-1(2) via radiative transition in the superradiance (SR) mode. It is found that a production efficiency (from S-1(0) to D-1(2)) of more than similar to 30% is achieved within a time interval of a few nanoseconds for a Ba density n > 10(19) m(-3). Several key features of SR important for future PSR experiments are also studied.

DOI： 10.7566/JPSJ.83.044301

Iodine molecule for neutrino mass spectroscopy: Ab initio calculation of spectral rate 査読

Tashiro, M., Ehara, M., Kuma, S., Miyamoto, Y., Sasao, N., Uetake, S., Yoshimura, M.

Progress of Theoretical and Experimental Physics 2014 ( 1 ) 2014年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：OXFORD UNIV PRESS INC

It has recently been argued that atoms and molecules may become good targets for determining neutrino parameters still undetermined, if the atomic/molecular process is enhanced by a new kind of coherence. We compute the photon energy spectrum rate arising from coherent radiative neutrino pair emission processes of metastable excited states of I-2 and its isovalent molecules, vertical bar Av > -> vertical bar Xv'> + gamma +nu(i)nu(j) and vertical bar A' v > -> vertical bar Xv '> + gamma + nu(i)nu(j), with gamma an IR photon and nu(i(j)) the i (j)th neutrino mass eigenstates, and show how fundamental neutrino parameters may be determined. Energies of electronically excited states of I-2, including the effect of spin-orbit couplings, were calculated by the multiconfigurational second-order perturbation (CASPT2) method. Summation over many vibrational levels of intermediate states is fully incorporated. Unlike atomic candidates with a much larger energy difference, such as Xe, I-2 transitions from a vibrational level A(v = 0) to X(v' = 24) give us an opportunity to determine the mass type (Majorana vs Dirac distinction) and theMajorana CPV (charge-conjugation parity violating) phases, although the rate is much smaller.

DOI： 10.1093/ptep/ptt118

Validation of XCH <inf>4</inf> derived from SWIR spectra of GOSAT TANSO-FTS with aircraft measurement data 査読

Inoue, M., Morino, I., Uchino, O., Miyamoto, Y., Saeki, T., Yoshida, Y., Yokota, T., Sweeney, C., Tans, P.P., Biraud, S.C., Machida, T., Pittman, J.V., Kort, E.A., Tanaka, T., Kawakami, S., Sawa, Y., Tsuboi, K., Matsueda, H.

Atmospheric Measurement Techniques 7 ( 9 ) 2987 - 3005 2014年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：COPERNICUS GESELLSCHAFT MBH

Column-averaged dry-air mole fractions of methane (XCH4), retrieved from Greenhouse gases Observing SATellite (GOSAT) short-wavelength infrared (SWIR) spectra, were validated by using aircraft measurement data from the National Oceanic and Atmospheric Administration (NOAA), the US Department of Energy (DOE), the National Institute for Environmental Studies (NIES), the HIAPER Pole-to-Pole Observations (HIPPO) program, and the GOSAT validation aircraft observation campaign over Japan. In the calculation of XCH4 from aircraft measurements (aircraft-based XCH4), other satellite data were used for the CH4 profiles above the tropopause. We proposed a data-screening scheme for aircraft-based XCH4 for reliable validation of GOSAT XCH4. Further, we examined the impact of GOSAT SWIR column averaging kernels (CAK) on the aircraft-based XCH4 calculation and found that the difference between aircraft-based XCH4 with and without the application of the GOSAT CAK was less than +/- 9 ppb at maximum, with an average difference of -0.5 ppb. We compared GOSAT XCH4 Ver. 02.00 data retrieved within +/- 2 degrees or +/- 5 degrees latitude-longitude boxes centered at each aircraft measurement site with aircraft-based XCH4 measured on a GOSAT overpass day. In general, GOSAT XCH4 was in good agreement with aircraft-based XCH4. However, over land, the GOSAT data showed a positive bias of 1.5 ppb (2.0 ppb) with a standard deviation of 14.9 ppb (16.0 ppb) within the +/- 2 degrees (+/- 5 degrees) boxes, and over ocean, the average bias was 4.1 ppb (6.5 ppb) with a standard deviation of 9.4 ppb (8.8 ppb) within the +/- 2 degrees (+/- 5 degrees) boxes. In addition, we obtained similar results when we used an aircraft-based XCH4 time series obtained by curve fitting with temporal interpolation for comparison with GOSAT data.

DOI： 10.5194/amt-7-2987-2014

Observation of new near infrared emission band systems of small bismuth clusters in solid neon matrix 査読

Wakabayashi, T., Tomioka, M., Wada, Y., Miyamoto, Y., Tang, J., Kawaguchi, K., Kuma, S., Sasao, N., Nanjo, H., Uetake, S., Yoshimura, M., Nakano, I.

European Physical Journal D 67 ( 2 ) 2013年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：SPRINGER

Laser induced fluorescence (LIF) spectroscopy was applied to small bismuth clusters embedded in a solid neon matrix at 3 K. Near infrared (NIR) optical emission spectra were recorded in a range of 6200-11 600 cm(-1) by an excitation with 1.79 eV photons using a pulsed dye laser system. Three new NIR band systems were identified by their origin bands at 8207, 9625 and 11 395 cm(-1). Each of the NIR systems exhibited the vibrational progression with a common lower state frequency at 151 cm(-1). Temporal decay profiles for selected NIR emission bands showed upper state lifetimes on the order of a hundred of microseconds, explainable by the transition between mixed spin states. Low-lying electronic states for small bismuth clusters, Bi-n (n = 2-4), are discussed along the theory and experiment reported so far.

DOI： 10.1140/epjd/e2012-30529-x

Infrared spectroscopy of chloromethyl radical in solid parahydrogen and its nuclear spin conversion 査読

Miyamoto, Y., Tsubouchi, M., Momose, T.

Journal of Physical Chemistry A 117 ( 39 ) 9510 - 9517 2013年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

We present high-resolution infrared absorption spectra of chloromethyl radical produced by in situ UV photolysis of chloroiodomethane isolated in solid parahydrogen. The radicals were stable over a few days in solid parahydrogen kept at 3.6 K. Analysis of the rotation-vibration spectra revealed that the radical exhibited quantized one-dimensional rotational motion about the C-Cl bond, while the ortho and para nuclear spin species were still clearly distinguishable in the spectra. Temporal change of the spectra indicated that the nuclear spin conversion between the ortho and para nuclear spin species of the radical in solid parahydrogen occurred in a time scale of a few hours at 3.6 K. It was also. found that the nuclear spin conversion became significantly slower in a higher concentration of chloroiodomethane.

DOI： 10.1021/jp312122p

Atmospheric column-averaged mole fractions of carbon dioxide at 53 aircraft measurement sites 査読

Miyamoto, Y., Inoue, M., Morino, I., Uchino, O., Yokota, T., Machida, T., Sawa, Y., Matsueda, H., Sweeney, C., Tans, P.P., Andrews, A.E., Patra, P.K.

Atmospheric Chemistry and Physics 13 ( 10 ) 5265 - 5275 2013年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：COPERNICUS GESELLSCHAFT MBH

Atmospheric column-averaged mole fractions of carbon dioxide (XCO2) at 53 locations around the world were derived from aircraft measurements covering the altitude range of about 1-10 km. We used CO2 vertical profile measurements from three major carbon cycle programs, a global climatological data set of air number density profiles and tropopause height for calculating XCO2 for the period of 2007-2009. Vertical profiles of the CO2 mixing ratio are complemented by tall tower data up to 400 m from the earth's surface and by simulated profiles in the stratosphere from a chemistry-transport model. The amplitude of the seasonal cycle of calculated XCO2 values shows clear latitudinal dependence, and the amplitude decreases from about 10 ppm at high latitudes in the Northern Hemisphere to at most 2 ppm in the tropics and the Southern Hemisphere. The uncertainties of XCO2 were estimated from assumptions about CO2 profiles for each flight. Typically, uncertainties were less than 1 ppm; thus, this data set is within the level of uncertainty needed for primary validation of XCO2 measurements by the Greenhouse gases Observing SATellite (GOSAT) and by future satellite missions for monitoring greenhouse gases.

DOI： 10.5194/acp-13-5265-2013

4.8 μm difference-frequency generation using a waveguide-PPLN crystal and its application to mid-infrared Lamb-dip spectroscopy 査読

Kuma S, Miyamoto Y, Tsutsumi K, Sasao N, Uetake S

Optics Letters 38 ( 15 ) 2825 - 2828 2013年

Validation of XCO <inf>2</inf> derived from SWIR spectra of GOSAT TANSO-FTS with aircraft measurement data 査読

Inoue, M., Morino, I., Uchino, O., Miyamoto, Y., Yoshida, Y., Yokota, T., Machida, T., Sawa, Y., Matsueda, H., Sweeney, C., Tans, P.P., Andrews, A.E., Biraud, S.C., Tanaka, T., Kawakami, S., Patra, P.K.

Atmospheric Chemistry and Physics 13 ( 19 ) 9771 - 9788 2013年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：COPERNICUS GESELLSCHAFT MBH

Column-averaged dry air mole fractions of carbon dioxide (XCO2) retrieved from Greenhouse gases Observing SATellite (GOSAT) Short-Wavelength InfraRed (SWIR) observations were validated with aircraft measurements by the Comprehensive Observation Network for TRace gases by AIrLiner (CONTRAIL) project, the National Oceanic and Atmospheric Administration (NOAA), the US Department of Energy (DOE), the National Institute for Environmental Studies (NIES), the HIAPER Pole-to-Pole Observations (HIPPO) program, and the GOSAT validation aircraft observation campaign over Japan. To calculate XCO2 based on aircraft measurements (aircraft-based XCO2), tower measurements and model outputs were used for additional information near the surface and above the tropopause, respectively. Before validation, we investigated the impacts of GOSAT SWIR column averaging kernels (CAKs) and the shape of a priori profiles on the aircraft-based XCO2 calculation. The differences between aircraft-based XCO2 with and without the application of GOSAT CAK were evaluated to be less than +/-0.4 ppm at most, and less than +/-0.1 ppm on average. Therefore, we concluded that the GOSAT CAK produces only a minor effect on the aircraft-based XCO2 calculation in terms of the overall uncertainty of GOSAT XCO2. We compared GOSAT data retrieved within +/-2 or +/-5 degrees latitude/longitude boxes centered at each aircraft measurement site to aircraft-based data measured on a GOSAT overpass day. The results indicated that GOSAT XCO2 over land regions agreed with aircraft-based XCO2, except that the former is biased by -0.68 ppm (-0.99 ppm) with a standard deviation of 2.56 ppm (2.51 ppm), whereas the averages of the differences between the GOSAT XCO2 over ocean and the aircraft-based XCO2 were -1.82 ppm (-2.27 ppm) with a standard deviation of 1.04 ppm (1.79 ppm) for +/-2 degrees (+/-5 degrees) boxes.

DOI： 10.5194/acp-13-9771-2013

Diffusion of hydrogen fluoride in solid parahydrogen 査読

Ooe, H., Miyamoto, Y., Kuma, S., Kawaguchi, K., Nakajima, K., Nakano, I., Sasao, N., Tang, J., Taniguchi, T., Yoshimura, M.

Journal of Chemical Physics 138 ( 21 ) 2013年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER INST PHYSICS

We studied diffusion of hydrogen fluoride (HF) in solid parahydrogen (pH(2)) around 4 K. Diffusion rates were determined from time dependence of FT-IR spectra of HF monomers. The absorption of HF monomers shows temporal decay due to dimerization reaction via diffusion. It was found that the rates are affected by the sample temperature, the initial HF concentration, and annealing of samples. The observed non-Arrhenius-type temperature dependence suggests that the diffusion is dominated by a quantum tunneling process, that is, "quantum diffusion." Deceleration of the diffusion in condensed samples and acceleration in annealed samples were also observed. These results can be attributed to the fact that lower periodicity of samples due to impurities or defects suppresses the quantum tunneling. It seems to be difficult to explain the observed dependences by three possible diffusion mechanisms, exchange of chemical bonds, direct cyclic exchange, and exchange with mobile vacancy. Therefore, we propose a hypothetical mechanism by exchange of vacancies originating from quantum effect. (C) 2013 AIP Publishing LLC.

DOI： 10.1063/1.4808035

Coherence decay measurement of v = 2 vibrons in solid parahydrogen 査読

Kuma, S., Miyamoto, Y., Nakajima, K., Fukumi, A., Kawaguchi, K., Nakano, I., Sasao, N., Tanaka, M., Tang, J., Taniguchi, T., Uetake, S., Wakabayashi, T., Yoshimi, A., Yoshimura, M.

Journal of Chemical Physics 138 ( 2 ) 2013年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER INST PHYSICS

The coherence decay of the v = 2 vibrational state (vibrons) of solid parahydrogen was measured via time-resolved coherent anti-Stokes Raman spectroscopy. We found that the decay curve has a non-exponential time profile in the time scale of 200 ns at a low temperature below 5 K and a low orthohydrogen impurity concentration (similar to 0.01%). This behavior, as also observed in the case of the v = 1 vibrons, represents a signature of band structure of the v = 2 state in the solid phase. The maximum coherence decay time of 50 ns in an exponential part was achieved, which shows excellence of the v = 2 state for coherent processes. We also found that finite temperatures, orthohydrogen impurities, and other structural inhomogeneity accelerate the decay, hiding the non-exponential feature of the vibron band. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4773893]

DOI： 10.1063/1.4773893