Asuka Fujii 교수

Size-dependent development of the hydrogen bond network structure in large sized clusters of protonated water, H+(H2O)n (n = 4 to 27), was probed by infrared spectroscopy of OH stretches. Spectral changes with cluster size demonstrate that the chain structures at small sizes (n less, similar 10) develop into two-dimensional net structures (approximately 10 < n < 21), and then into nanometer-scaled cages (n >/= 21).

Although messenger mediated spectroscopy is a widely-used technique to study gas phase ionic species, effects of messengers themselves are not necessarily clear. In this study, we report infrared photodissociation spectroscopy of H(+)(H(2)O)(6)·M(m) (M = Ne, Ar, Kr, Xe, H(2), N(2), and CH(4)) in the OH stretch region to investigate messenger(M)-dependent cluster structures of the H(+)(H(2)O)(6) moiety. The H(+)(H(2)O)(6), the protonated water hexamer, is the smallest system in which both the H(3

Precisely size-selected protonated water clusters H+(H2O)n (n=20–200) were studied by IR spectroscopy to provide insights into the structures of large-scale H-bonded water networks. The spectral features reveal that cluster structures gradually approach that of the bulk-water network and involve a greater number of four-coordinate water molecules with increasing cluster size (see picture). Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such document

Size-selective infrared (IR) spectroscopy of gas phase water-containing clusters is performed to probe microscopic natures of hydrogen-bonded water networks. Size-selective observation is extended to the size range of a few tens to hundreds of molecules to bridge the gap between simple but unique networks in small-sized water clusters and those in bulk water. IR spectra of two types of large water-containing clusters, phenol-(H2O) n (n < ∼50) and H+(H2O) n (n ⩽ 221), are measured in the OH stret

Various vibrational spectroscopic techniques combined with vacuum-ultraviolet one-photon ionization mass spectrometry have recently been developed for jet-cooled molecules and clusters. These techniques open general applications of size-selected infrared and also Raman spectroscopies to neutral clusters by overcoming difficulties in the conventional vibrational spectroscopic methods for jet-cooled clusters. Their spectroscopic principles have been demonstrated by investigations for neutral clust

The nature of water networks exposed to ionizing radiation is important in various radiation-related chemistry and biology. To understand structural evolution of ionized water networks at the molecular level, we report here infrared spectra of watercluster radical cations (H2O)n+ (n = 3 − 11) in the gas phase. Spectral features of free OH stretch modes are quite similar to those of protonated waterclustersH+(H2O)n, of which the hydrogen-bond network structures have been revealed. In addition, we

The CH/pi interaction energies between benzene and halomethanes (CH(2)Cl(2) and CHCl(3)) were accurately determined. Two-color ionization spectroscopy was applied to the benzene-CH(2)Cl(2) and -CHCl(3) clusters, and the binding energies in the neutral ground state, i.e. the CH/pi interaction energies in these model cluster systems, were precisely evaluated on the basis of the dissociation threshold measurements of the clusters in the cationic state and the ionization potential value of the bare

Infrared spectra of phenol−X (X = C6H6, C2H4, and C2H2) clusters in the neutral and cationic ground states were observed in the OH stretching vibrational region. For the neutral ground state, infrared−ultraviolet double resonance spectroscopy was utilized to observe the infrared spectra. A small low-frequency shift of the OH vibration of the phenol site in all the clusters represented the characteristic feature for their π-hydrogen-bonded structures, which were also confirmed by density function

Infrared (IR) spectra of benzene–(water)n cluster cations (Bz–Wn)+ (n = 1–6) in the OH and CH stretching vibrational region were observed in order to investigate their structure and reactivity. The cluster cations were prepared by two different production methods: one is due to collision between bare benzene cations and water clusters; and the other utilizes resonance enhanced multiphoton ionization (REMPI) of neutral clusters. The former method prefers the production of the most stable isomer c

The CH stretching vibrations of the benzene–Ar, toluene–Ar, and ethylbenzene–Ar clusters prepared in jet expansion were observed in both the neutral and cationic ground states by using infrared–ultraviolet double resonance and infrared photodissociation spectroscopy, respectively. Vibrational frequencies for the in-plane modes of the clusters have been found to be practically the same as those of the corresponding bare molecules. The aromatic CH stretching vibrations showed high frequency shifts

CH stretching vibrations of jet-cooled benzene−acetylene and several aromatics−acetylene clusters were observed in order to characterize the intermolecular interaction, so-called activated CH/π interaction between an acidic CH group and π-electrons. The infrared−ultraviolet double resonance spectroscopic techniques were used for measuring their vibrational spectra. The antisymmetric CH stretching vibration of the acetylene moiety exhibits a remarkable low-frequency shift upon the cluster formati

The OH stretching vibration of jet-cooled phenol-N2 in the neural and cationic ground states was observed by using infrared–ultraviolet double resonance spectroscopy and infrared photodissociation spectroscopy, respectively. The OH vibration showed a small but significant low-frequency shift of 5 cm−1 upon the cluster formation in the neutral, while the shift drastically increased up to 159 cm−1 in the cation. These results represent the direct evidence of the in-plane cluster structure, in whic

The CH/π interaction energies in benzene-alkane model clusters were precisely determined by laser spectroscopy and theoretical calculations. Two-color resonant two-photon ionization spectroscopy was employed to experimentally determine the interaction energies with isomer selectivity. High precision ab initio calculations were also performed to evaluate the CCSD(T) level interaction energies of various isomers at the basis set limit. Binary clusters of benzene with ethane, propane, n-butane, iso