Energy transfer and photodegradation of Perylene Orange:LDS821 system in poly(methl methacrylate)

ArticleApplied Optics. 45(21): 5385-5390 (2006)journal articl

Photoinduced reactions of chloroacetone in solid Ar: Identification of CH2=COCICH3

The UV light-induced reactions of chloroacetone in a cryogenic Ar matrix were investigated using infrared spectroscopy. The photoinduced isomerisations of gauche-chloroacetone to syn-chloroacetone and hypochlorous acid 1-methylethenyl ester were confirmed by comparing the experimental and calculated spectra. In addition, the photolysis products were found to be CH2double bond; length as m-dashCdouble bond; length as m-dashO and a cyclopropanone⋯HCl complex. The cyclopropanone⋯HCl complex was further decomposed into CH2double bond; length as m-dashCH2, CO and HCl. The hypochlorous acid 1-methylethenyl ester was further isomerized to 2-chloro-2-methyloxirane.ArticleCHEMICAL PHYSICS LETTERS. 614:258-262 (2014)journal articl

Density functional theory studies on the addition and abstraction reactions of OH radicals with terephthalate dianions

The addition and abstraction reactions of OH radicals with terephthalate dianions are investigated by density functional theory calculations that include solvent effects. Geometry optimizations of the reactants, products, and transition state species are performed for the potential reaction paths. For the addition reactions, those targeting the ipso- and ortho-carbons are predicted to be exoergic. The H-atom abstraction reaction is also predicted to be exoergic. On the basis of the rate constants calculated by means of the transition state theory, the H-atom abstraction reaction is determined to be the thermochemically favored path. (C) 2012 Wiley Periodicals, Inc.ArticleINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY. 113(4):418-422 (2013)journal articl

Computational study of the reaction between chloroacetone and OH radical

In this study, the reaction of the chloroacetone with OH radical was studied theoretically using density functional theory (DFT) and transition state theory. The potential energy surface of the reaction was calculated at the CAM-B3LYP/6-311++G(2d,2p) and M06-2X/6-311++G(2d,2p) levels. We initially considered four possible reaction paths: (1) the hydrogen atom abstraction from chloroacetone by OH radical; (2) the addition of the OH radical to the carbonyl carbon; (3) chlorine atom abstraction; and (4) SN2 displacement. The conventional transition state theory was employed to calculate the rate constants. The hydrogen abstraction from the ?CH2Cl group was found to be dominant. Since, the predicted total rate constant at the CAM-B3LYP/6-311++G(2d,2p) level was in good agreement with the experimental value at 298 K, the level of theory used in this study to describe this reaction is appropriate.ArticleCOMPUTATIONAL AND THEORETICAL CHEMISTRY. 1020:108-112 (2013)journal articl

Development of a Training-Assist Robotic System Adapting to Individual Motor Abilities in Virtual Tennis Task

The present paper develops a training-assist robotic system that can adapt a reference hand motion for a virtual tennis task to individual motor abilities. The system first measures maximum hand force and velocity in reaching arm movements prior to the training, and designs a suitable reference trajectory for teaching motion smoothness and timing in the virtual tennis task based on the measured results. A quantitative index for evaluating task performance and motor functions are then defined with consideration of task dynamics. Finally, the effectiveness of the developed training system is validated through a set of preliminary training experiments with health subjects

Matrix isolation studies of 185 nm light-induced cage reactions of o-chlorobenzaldehyde

VUV light photolysis of o-chlorobenzaldehyde (CBA) has been investigated by infrared spectroscopy in cryogenic Ar and O-2 matrices. Previously reported photoinduced rotational isomerization from anti- to syn-CBA was confirmed in the Ar matrix. In addition, absorption bands associated with photoinduced rearrangement to benzoyl chloride were observed accompanying the weak bands due to the CO photolysis product. However, in the reactive O-2 matrix, isomerization was observed and there was no evidence of benzoyl chloride formation. A kinetic analysis revealed that rearrangement was a minor process under the present excitation energy. The TD-B3LYP calculations show that as the excitation energy increases the predissociation channel will open and the repulsive (1)(pi, sigma(c-a)*) and 1(eta, sigma(c-a)*) states are directly achievable by the 185 nm excitation. Photoinduced rearrangement will be caused by the reaction of thus dissociated cage pairs.ArticleJOURNAL OF MOLECULAR STRUCTURE. 1025:48-52 (2012)journal articl

Photoinduced rotamerization and dissociation of o-fluorobenzoyl chloride in solid Ar

UV light-induced reactions of o-fluorobenzoyl chloride (FBC) were investigated using infrared spectroscopy in a cryogenic Ar matrix. Photoinduced rotational isomerization from anti- to gauche-FBC was confirmed by comparison with calculated spectra. In addition, photolysis products were found to be ketene species (6-chloro-2-fluoro-2,4-cyclohexadien-1-ylidenemethanone), o-fluorobenzoyl radical, o-chlorofluorobenzene, m-chlorofluorobenzene and CO.ArticleCHEMICAL PHYSICS LETTERS. 613:34-39 (2014)journal articl

Photo-electric conversion in dye-doped nanocrystalline titania films

Influences of the titania nanostructure and dye dispersion in a dye-doped titania electrode on its photoelectric conversion property were investigated by simple spectroscopic and electric measurements. The dye-doped nanocrystalline titania electrodes were prepared on the glass plates coated with ITO and normal crystalline titania films by the following two procedures: (1) the dye-doped titania gel films were prepared from a titanium alkoxide solution containing the dye and then steam-treated, and (2) the titanium alkoxide sol containing the dye was refluxed and then spread onto the plates. The photocurrent quantum efficiency remarkably increased by the steam treatment and the reflux compared to that of the untreated dye-doped electrode consisting of amorphous titania gel. The efficiency in the former was higher than that in the latter. The growth and crystallization of the titania particles and the decrease in the defect density by these treatments improved the electric conductivity. The steam treatment was the more prominent method because it enhanced the electric conductivity of the titania depending on its nanostructure and the dye-titania interaction depending on the dye dispersion. These factors appear to play important roles in transport in the electron through the electrode.ArticleJOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY. 207(2-3):204-208 (2009)journal articl