Ken‐ichi Inoue

Two-dimensional heterodyne-detected vibrational sum-frequency generation (2D HD-VSFG) spectroscopy is applied to study the ultrafast vibrational dynamics of water at positively charged aqueous interfaces, and 2D HD-VSFG spectra of cetyltrimethylammonium bromide (CTAB)/water interfaces in the whole hydrogen-bonded OH stretch region (3000 cm(-1) ≤ ωpump ≤ 3600 cm(-1)) are measured. 2D HD-VSFG spectrum of the CTAB/isotopically diluted water (HOD-D2O) interface exhibits a diagonally elongated bleach

Femtosecond vibrational dynamics at the air/water interface is investigated by time-resolved heterodyne-detected vibrational sum frequency generation (TR-HD-VSFG) spectroscopy and molecular dynamics (MD) simulation. The low- and high-frequency sides of the hydrogen-bonded (HB) OH stretch band at the interface are selectively excited with special attention to the bandwidth and energy of the pump pulses. Narrow bleach is observed immediately after excitation of the high-frequency side of the HB OH

The uniqueness of water originates from its three-dimensional hydrogen-bond network, but this hydrogen-bond network is suddenly truncated at the interface and non-hydrogen-bonded OH (free OH) appears. Although this free OH is the most characteristic feature of interfacial water, the molecular-level understanding of its dynamic property is still limited due to the technical difficulty. We study ultrafast vibrational relaxation dynamics of the free OH at the air/water interface using time-resolved

Molecular-level elucidation of hydration at biological membrane interfaces is of great importance for understanding biological processes. We studied ultrafast hydrogen-bond dynamics at a zwitterionic phosphatidylcholine/water interface by two-dimensional heterodyne-detected vibrational sum frequency generation (2D HD-VSFG) spectroscopy. The obtained 2D spectra confirm that the anionic phosphate and cationic choline sites are individually hydrated at the interface. Furthermore, the data show that

Hot carriers at metal surfaces can drive nonthermal reactions of adsorbates. Characterizing nonequilibrium statistics among various degrees of freedom in an ultrafast time scale is crucial to understand and develop hot carrier-driven chemistry. Here we demonstrate multidimensional vibrational dynamics of carbon monoxide (CO) on Cu(100) along hot-carrier induced desorption studied by using time-resolved vibrational sum-frequency generation with phase-sensitive detection. Instantaneous frequency a

Electronic excitation of metal by intense laser pulses stimulates nuclear motions of adsorbates through nonadiabatic coupling, resulting in diffusion and desorption of adsorbates. These processes take place via precursor states: adsorbates whose vibrational modes with respect to substrate are highly excited. This paper reports the dynamics of precursor states of CO on Pt(111) probed by use of infrared-visible sum frequency generation with phase-sensitive detection, which allows us to obtain the

The pulmonary surfactant monolayer is indispensable for the respiratory system. Recently, it was reported that some unsaturated lipids of the pulmonary surfactants are oxidized by low-level ozone in ambient air. However, the molecular-level understanding of the reaction mechanism is still limited due to technical difficulties. We applied heterodyne-detected sum frequency generation (HD-SFG) spectroscopy to probe the reaction process of an unsaturated phospholipid monolayer (1-palmitoyl-2-oleoyl-

Ultrafast hydrogen-bond fluctuation dynamics of water at charged monolayer interfaces were studied by the use of steady-state and 2D heterodyne-detected vibrational sum frequency generation (HD-VSFG) spectroscopy. Specifically, the effect of hydrogen-bond ability of the interface on the dynamics was investigated by comparing two monolayer interfaces that provide different hydrogen bond abilities: hydrogen bonding octadecylammonium (ODA) monolayer (pH = 2) and non-hydrogen bonding 1,2-dipalmitoyl

A new cobalt (Co) salicide technology for sub-quarter micron CMOS transistors has been developed using high-temperature sputtering and in situ vacuum annealing. Sheet resistance of 11 /spl Omega///spl square/ for both gate electrode and diffusion layer was obtained with 5-nm-thick Co film. No line width dependence of sheet resistance was observed down to 0.15-/spl mu/m-wide gate electrode and 0.33-/spl mu/m-wide diffusion layer. The high temperature sputtering process led to the growth of epitax

A new cobalt (Co) salicide technology using high-temperature sputtering and in-situ vacuum annealing process has been developed. This technology is a simple process without additional ion implantation and metal deposition to promote silicidation and to suppress oxidation of Co film. No line width dependence of sheet resistances was achieved down to for 0.15 /spl mu/m gate electrode and 0.33 /spl mu/m for diffusion layer. Sheet resistance of 11 /spl Omega//sq. for both gate electrode and diffusio

We developed a new fast scintillation detector using proportional-mode silicon avalanche photodiode (Si-APD) for nuclear forward scattering experiments using high-energy synchrotron X-rays >30 keV. After a test of a prototype detector with a lead-loaded plastic scintillator (EJ-256, Eljen Technology) and proportional-mode Si-APD (S8664-3796(X), Hamamatsu Photonics) as a photodetector, we fabricated a four-channel detector using four 3×3×3 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xm

Abstract The effect of the head group on the oxidation of unsaturated phospholipids under low-level ozone was investigated. The phospholipids with head groups of glycerol and choline show different surface-pressure profiles but similar degradation kinetics of the C=C moieties was observed by heterodyne-detected sum frequency generation spectroscopy.