Kyushu University · Materials Science
Professor Akira Terasaki's research lab specializes in ultrafast spectroscopy, molecular dynamics, and the optical characterization of low-dimensional systems and free ions. The lab focuses on developing advanced spectroscopic techniques—such as cavity ringdown and photon-trap spectroscopy—to study electronic transitions, hyperfine structures, and photodissociation dynamics in clusters, ions, and molecular systems with high sensitivity. Their work spans from fundamental studies of transition metal ions and dimers to the dynamics of cluster-surface collisions and the freezing behavior of nanoscale water droplets.
Figures are computed from collected data and may differ slightly.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFemtosecond spectroscopy of vanadyl phthalocyanines in various molecular arrangementsAkira Terasaki, Masahiro Hosoda, Tatsuo Wada, Hirokazu Tada, Atsushi Koma, Akira Yamada, Hiroyuki Sasabe, Anthony F. Garito, and Takayoshi KobayashiCite this: J. Phys. Chem. 1992, 96, 25, 10534–10542Publication Date (Print):December 1, 1992Publication History Published online1 May 2002Published inissue 1 December 1992https://pubs.acs.org/doi/10.1021/j100204a075https://
A novel experimental technique has been developed to observe a trace of optical absorption of free mass-selected ions. The technique combines a linear radio-frequency ion trap with a high-finesse optical cavity to perform cavity ring-down spectroscopy (photon-trap spectroscopy for generality), where the storage lifetime of photons in the cavity provides a sensitivity high enough to probe the trapped ions. Absorption spectra of the manganese ion Mn(+) are presented, showing hyperfine structures f
Dynamical processes involved in the collision of aluminum cluster anions, Al−N (4≤N≤25), with a silicon surface were investigated. Intact and fragment cluster anions, Al−n (n≤N), were produced upon the collision. The surf02ace-tangent and surface-normal recoil velocity components of these product a0n0ions were determined. The tangential recoil velocities of the fragment cluster anions were considerably slow, ranging from 5% to 30% of the velocity of the incident parent cluster anion, while the n
The optical spectrum of the manganese dimer ion, Mn2+, was obtained by measurement of the photodissociation action spectrum in the photon-energy range from 1.9 through 5.6 eV. The spectrum was analyzed by calculating its electronic and geometric structures using density functional theory including nonlocal corrections. The simulation was in reasonable agreement with the experimental result, allowing the assignment of the electronic states involved in the optical transitions. The ground state was
Freezing processes are reported for pure-water droplets generated in a vacuum in the size range of 49-71 μm in diameter. The process is characterized for each size by measurement of a freezing curve, where the fraction of frozen droplets is evaluated as a function of time. The 49 μm droplet was found to freeze at a time between 7.0 and 7.9 ms after being generated at room temperature, where the fraction of frozen droplets increased from 5% to 95%; the freezing time was thus distributed statistic
Cavity ringdown spectroscopy, or photon-trap spectroscopy for generality, is shown to be applicable to a sample in the solid phase by theoretical and experimental studies. In the technique investigated, a solid in a substrate form having optically flat parallel surfaces is inserted exactly normal to a light beam in a high-finesse optical cavity; the light reflected at the substrate surface is coupled back to the cavity and thus the optical loss is minimized. Thereby the trapping lifetime of phot
The optical spectrum of the manganese trimer ion, Mn3+, was obtained by measurement of the photodissociation cross section in the photon-energy range between 1.43 and 4.13 eV. Analysis of the spectrum by quantum-chemical calculations derived its electronic and geometric structures. The geometric structure was found to be an isosceles triangle (C2v) with bond lengths of 3.03 Å and an apex angle of 144°. The ground electronic state was found to be B217. The electronic structure of the valence orbi
The photodissociation processes of the manganese cluster ions Mnn+ (n=3 and 4) were investigated in the visible and near-infrared photon-energy ranges. The threshold energies were determined for the two-atom-loss channels by measurements of the spectra of the partial photodissociation cross sections. The binding energies of Mnn+ (n=3 and 4) were obtained by using these threshold energies and the known bond dissociation energy of Mn2+. The bond dissociation energies of Mn3+, D0(Mn2+⋯Mn), and Mn4+
Clusters of atoms/molecules show dynamics characteristic of the method of excitation. Two contrasted processes are discussed: (1) electronic excitation via single-photon absorption and (2) impulsive excitation of nuclear motions by surface impact. Process 1 is exemplified by photodissociation dynamics of size-selected metal cluster ions. The electronic energy is converted most likely to vibrational energy of internal modes; dissociation follows via statistical mechanism to produce energetically
X-ray absorption spectroscopy (XAS) of size-selected free cerium-oxide cluster ions has been carried out by employing an ion trap. X-ray absorption spectra of and were obtained in the energy range of the Ce M-edge. The spectra consisted of two prominent peaks corresponding to Ce M5- and M4-'white line' peaks. The photon energies of the peaks showed that the charge state of Ce in was comparable with a formal valence number. On the other hand, the estimated charge state of Ce in was much smaller t
Electron counting is a concept that often governs properties of molecules, clusters, and complexes. Here we explore silver clusters doped with a transition-metal atom, where it has been an issue whether or not 3d electrons delocalize to participate in electron counting. The experiment is performed on Ag<sub><i>N</i></sub>M<sup>+/-</sup> (M = Sc-Ni) clusters to examine their stability through chemical reactivity, enabling systematic control of the number of valence electrons by the cluster size,
Open papers in the app to read, cite, and organize with AI.