Infrared-vacuum ultraviolet-pulsed field ionization-photoelectron study of CH(3)I(+) using a high-resolution infrared laser

By using a high-resolution single mode infrared-optical parametric oscillator laser to prepare CH(3)I in single (J,K) rotational levels of the nu(1) (symmetric C-H stretching) =1 vibrational state, we have obtained rovibrationally resolved infrared-vacuum ultraviolet-pulsed field ionization-photoelectron (IR-VUV-PFI-PE) spectra of the CH(3)I(+)(X(2)E(32);nu(1)(+)=1;J(+),P(+)) band, where (J,K) and (J(+),P(+)) represent the respective rotational quantum numbers of CH(3)I and CH(3)I(+). The IR-VUV-PFI-PE spectra observed for K=0 and 1 are found to have nearly identical structures. The IR-VUV-PFI-PE spectra for (J,K)=(5,0) and (7, 0) are also consistent with the previous J-selected IR-VUV-PFI-PE measurements. The analysis of these spectra indicates that the photoionization cross section of CH(3)I depends strongly on DeltaJ(+)=J(+)-J: but not on J and K. This observation lends strong support for the major assumption adopted for the semiempirical simulation scheme, which has been used for the simulation of the origin bands observed in VUV-PFI-PE study of polyatomic molecules. Using the state-to-state photoionization cross sections determined in this IR-VUV study, we have obtained excellent simulation of the VUV-PFI-PE origin band of CH(3)I(+)(X (2)E(32)), yielding more precise IE(CH(3)I)=76 930.7+/-0.5 cm(-1) and nu(1) (+)=2937.8+/-0.2 cm(-1).     

A vacuum ultraviolet laser photoionization and pulsed field ionization study of nascent S(3P2,1,0) and S(1D2) formed in the 193.3 nm photodissociation of CS2

The photoionization efficiency (PIE) and pulsed field ionization-photoion (PFI-PI) spectra for sulfur atoms S(3P2,1,0) and S(1D2) resulting from the 193.3 nm photodissociation of CS2 have been measured using tunable vacuum ultraviolet (vuv) laser radiation in the frequency range of 82 750-83 570 cm(-1). The PIE spectrum of S(3P2,1,0) near their ionization threshold exhibits steplike structures. On the basis of the velocity-mapped ion-imaging measurements, four strong autoionizing peaks observed in the PIE measurement in this frequency range have been identified to originate from vuv excitation of S(1D2). The PFI-PI measurement reveals over 120 previously unidentified new Rydberg lines. They have been assigned as Rydberg states [3p3(4S composite function nd3 D composite function (n=17-64)] converging to the ground ionic state S+(4S composite function) formed by vuv excitations of S(3P2,1,0). The converging limits of these Rydberg series have provided more accurate values, 82 985.43+/-0.05, 83 162.94+/-0.05, and 83 559.04+/-0.05 cm(-1) for the respective ionization energies of S(3P0), S(3P1), and S(3P2) to form S+(4S composite function). The relative intensities of the PFI-PI bands for S(3P0), S(3P1), and S(3P2) have been used to determine the branching ratios for these fine structure states, S(3P0):S(3P1):S(3P2)=1.00:1.54:3.55, produced by photodissociation of CS2 at 193.3 nm.     

A new class of isocyanide-containing rhenium(I) bipyridyl luminophore with readily tunable and highly environmentally sensitive excited-state properties

A new class of readily tunable and highly environmentally sensitive luminescent rhenium(I) tetra(isocyano)bipyridyl complexes has been synthesized and characterized, and their luminescent properties have been investigated. Preliminary studies showed that the metal-to-ligand charge-transfer [dpi(Re) --> pi*(bpy)] absorption and emission are extremely sensitive to the nature of the solvent and the rigidity of the environment.     

Studies of "pinwheel-like" bis[1,8,15,22-tetrakis(3-pentyloxy)phthalocyaninato] rare earth(III) double-decker complexes

Homoleptic bis(phthalocyaninato) rare-earth double-deckers complexes [M(III)[Pc(alpha-OC5H11)4]2] (M = Eu, Y, Lu; Pc(alpha-OC5H11)4 = 1,8,15,22-tetrakis(3-pentyloxy)phthalocyaninate) have been prepared by treating the metal-free phthalocyanine H2Pc(alpha-OC5H11)4 with the corresponding M(acac)3.nH2O (acac = acetylacetonate) in refluxing n-octanol. Due to the C4h symmetry of the Pc(alpha-OC5H11)4 ligand and the double-decker structure, all the reactions give a mixture of two stereoisomers with C4h and D4 symmetry. The former isomer, which is a major product, can be partially separated by recrystallization due to its higher crystallinity. The molecular structure of the major isomer of the Y analogue has been determined by single-crystal X-ray diffraction analysis. The metal center is eight-coordinate bound to the isoindole nitrogen atoms of the two phthalocyaninato ligands, forming a distorted square antiprism. Such an arrangement leads to an interesting pinwheel structure when viewed along the C4 axis, which assumes a very unusual S8 symmetry. The major isomers of all these double-deckers have also been characterized with a wide range of spectroscopic methods. A systematic investigation of their electronic absorption and electrochemical data reveals that the pi-pi interaction between the two Pc(alpha-OC5H11)4 rings is weaker than that for the corresponding unsubstituted or beta-substituted bis(phthalocyaninato) analogues.     

Decomposition rank and absorbing extensions of type I algebras

We prove the following: Let A and B be separable C^*-algebras. Suppose that B is a type I C^*-algebra such that

(i)

B has only infinite dimensional irreducible *-representations, and

(ii)

B has finite decomposition rank.

If

0→B→C→A→0     

The Particle In-Flight Characteristics in Plasma Spraying Process Measured by Phase Doppler Anemometry (PDA)

Detailed measurements of particle in-flight characteristics have been carried out using a PDA system for benchmarking as well as to provide further information to aid the development of simulation models. The parameters studied included four conditions of primary gas flow rate and carrier gas flow rate. The particle velocities, diameters, and the corresponding volume flux at different locations were obtained. Due to the one port particle injection arrangement, it was noted that particles in general sprayed with an angle deviated from the nozzle axis Z_n, to the opposite side of the powder feeder port. The particles would also deviate from the spraying cone axis with a divergence angle (). The deviation and divergence angles were examined under different plasma spraying conditions. The measurement data rates at different cross-sectional planes were also obtained so as to compare the results derived from the volume flux measurement and the actual coating on a substrate at the equivalent standoff distance. It was found that the spraying area obtained from the measurement-data-rate increased with downstream distance and a linear relationship between spraying area and distance was also established. Comparing the integrated results, it was noted that the spraying areas derived from the measurement data rate were close to the actual spraying areas obtained from the coordinate measurement machine (CMM) results.     

On chip single-cell separation and immobilization using optical tweezers and thermosensitive hydrogel

A novel approach appropriate for rapid separation and immobilization of a single cell by concomitantly utilizing laser manipulation and locally thermosensitive hydrogelation is proposed in this paper. We employed a single laser beam as optical tweezers for separating a target cell and locating it adjacent to a fabricated, transparent micro heater. Simultaneously, the target cell is immobilized or partially entrapped by heating the thermosensitive hydrogel with the micro heater. The state of the thermosensitive hydrogel can be switched from sol to gel and gel to sol by controlling the temperature through heating and cooling by the micro heater. After other unwanted cells are removed by the high-speed cleaning flow in the microchannel, the entrapped cell is successfully isolated. It is possible to collect the immobilized target cell for analysis or culture by switching off the micro heater and releasing the cell from the entrapment. We demonstrated that the proposed approach is feasible for rapid manipulation, immobilization, cleaning, isolation and extraction of a single cell. The experimental results are shown here.     

Strong optical force induced by morphology-dependent resonances

We consider the resonant optical force acting on a pair of transparent microspheres by the excitation of morphology-dependent resonance (MDR). The bonding and antibonding modes of the MDR correspond to strong attraction and repulsion, respectively. The dependence of the force on separation and the role of absorption are discussed. At resonance, the force can be enhanced by orders of magnitude such that it will dominate other relevant forces. We found that a stable binding configuration can be induced by the resonant optical force.