Probe Heating Method for the Analysis of Solid Samples Using a Portable Mass Spectrometer.

We previously reported on the development of a portable mass spectrometer for the onsite screening of illicit drugs, but our previous sampling system could only be used for liquid samples. In this study, we report on an attempt to develop a probe heating method that also permits solid samples to be analyzed using a portable mass spectrometer. An aluminum rod is used as the sampling probe.

Sensitive low-pressure dielectric barrier discharge ion source.

Rationale: We developed a novel highly sensitive soft ionization method: a low-pressure dielectric barrier discharge ionization (LP-DBDI) source. In this configuration, samples pass through the inside of a dielectric barrier discharge (DBD). Since samples pass through a DBD and its plasma jet, high ionization efficiency is expected.

High-throughput walkthrough detection portal for counter terrorism: detection of triacetone triperoxide (TATP) vapor by atmospheric-pressure chemical ionization ion trap mass spectrometry.

With the aim of improving security, a high-throughput portal system for detecting triacetone triperoxide (TATP) vapor emitted from passengers and luggage was developed. The portal system consists of a push-pull air sampler, an atmospheric-pressure chemical ionization (APCI) ion source, and an explosives detector based on mass spectrometry. To improve the sensitivity of the explosives detector, a novel linear ion trap mass spectrometer with wire electrodes (wire-LIT) is installed in the portal system.

Mass-selective axial ejection from a linear ion trap with a direct current extraction field.

We have developed a new mass-selective axial ejection method from a linear ion trap (LIT). In this method, a set consisting of a trap wire lens and an extraction wire lens positioned orthogonally to each other was placed between quadrupole rods. The trap wire lens confines the ions inside the trap, and the extraction wire axially extracts ions from the trap.

Solvent reorientation process in the "twisted" intramolecular charge-transfer process of cyanophenyldisilane-(H2O)2 cluster investigated by transient infrared spectroscopy.

The solvent reorientation process of the intramolecular charge-transfer (ICT) process of the (p-cyanophenyl)pentamethyldisilane-(H2O)2 (CPDS-(H2O)2) cluster in the excited-state was investigated by transient infrared (IR) absorption spectroscopy. It was found that there are at least two isomers in the charge-transfer (CT) state: one of the isomers exhibits a band of a pi-hydrogen-bonded OH stretch of the water moiety. Analyses of the IR spectra in the dominant isomers revealed that water molecules are hydrogen-bonded with each other in the CT state.

Direct observation of the solvent reorientation dynamics in the "twisted" intramolecular charge-transfer process of cyanophenyldisilane-water cluster by transient infrared spectroscopy.

The solvent reorientation dynamics of the intramolecular charge-transfer (ICT) process of the (p-cyanophenyl)pentamethyldisilane-H(2)O (CPDS-H(2)O) cluster was investigated by transient infrared (IR) absorption spectroscopy. Transient IR bands of two distinct charge-transfer (CT) states appeared in both the OH and the CN-stretching vibration regions. Analyses of the IR spectra and the time profiles of the transient bands revealed that the ICT process of the CPDS-H(2)O cluster proceeds in two steps.

First observation of a dihydrogen bond involving the Si-H group in phenol-diethylmethylsilane clusters by infrared-ultraviolet double-resonance spectroscopy.

We have experimentally identified a dihydrogen bond involving the Si-H group in phenol-diethylmethylsilane (DEMS) clusters for the first time by IR-UV double-resonance spectroscopy. Vibrational shifts to lower frequency of 21-29 cm(-1) were found for the OH stretching vibration of three isomers of the phenol-DEMS clusters. Spectral simulations based on the MP2 calculations also support our observation.

Determination of the equilibrium structure of the charge-transfer state of (p-Cyanophenyl)pentamethyldisilane by means of transient infrared spectroscopy.

An equilibrium structure of the charge-transfer (CT) state of (p-cyanophenyl)pentamethyldisilane was determined by transient infrared absorption spectroscopy of its CH stretching vibration region, and by the spectral simulation with quantum chemical calculations. It was found that a pattern of the CH stretching vibration bands of the CT state is substantially different from that of the S0 state. This band feature of the CT state was well reproduced assuming the planar sigma(Si-Si)pi* state, where the disilanyl group and the phenyl ring lie in the same plane.

Intramolecular charge-transfer process of jet-cooled (p-cyanophenyl)pentamethyldisilane: roles of the torsional motion and the Si-Si bond change.

To investigate the intramolecular charge-transfer (ICT) process of (p-cyanophenyl)pentamethyldisilane (CPDS), laser-induced fluorescence, dispersed fluorescence, and two-color resonance enhanced two-photon ionization spectra were measured in a jet-cooled isolated condition. Dual fluorescence of CPDS was observed from a ground vibrational level in the locally excited pipi state. Similar to an emission from the charge-transfer (CT) state in solution, one of the dual emissions of the isolated molecule in the jet was assigned as the CT emission.