Doppler-limited dye laser excitation spectroscopy of the CCN radical

The cw dye laser excitation spectrum of the $\text{A}\text{?}{}^2\text{Δ}\text{(000) ←}\text{X}\text{?}{}^2\text{Π}\text{(000)}$ vibronic transition of the CCN radical was observed between 21 205 and 21 335 cm^?1 with the Doppler-limited resolution, 0.04 cm^?1. The CCN radical was produced by reaction of microwave discharged CF₄ with CH₃CN. The observed spectrum was analyzed to determine rotational and centrifugal constants and effective spin-orbit and spin-rotation coupling constants for both the $\text{A}\text{?}{}^2\text{Δ}\text{(000)}$ and the $\text{X}\text{?}{}^2\text{Π}\text{(000)}$ states, and also the Λ-type doubling constants for the $\text{X}\text{?}{}^2\text{Π}\text{(000)}$ state. The constants determined reproduce the observed spectrum with an average deviation of 0.0027 cm^?1, and are considered to be precise enough for predicting the ground-state microwave transition frequencies. No evidence was found for perturbation in either the $\text{A}\text{?}{}^2\text{Δ}\text{(000)}$ or the $\text{X}\text{?}{}^2\text{Π}\text{(000)}$ state.     

High-resolution mass spectra of anti- and syn-isomers of acylferrocene oximes

High-resolution mass spectra of anti- and syn-acylferrocene oximes were examined at various ionizing voltages and fragmentation patterns of the oximes are presented. Significant differences between the anti- and syn-isomers were found in the fragmentation behaviour of the low voltage (15 to 20 eV) spectrum of formylferrocene oxime.     

Molecular dynamics and rheological properties of concentrated solutions of rodlike polymers in isotropic and liquid crystalline phases

A molecular theory is presented for the dynamics of rodlike polymers in concentrated solutions. The theory describes the rotational motion of rods in both the isotropic phase and the liquid crystalline phase. Combined with the molecular expression of the stress tensor, it also gives a unified rheological constitutive equation which predicts the nonlinear viscoelasticity in both phases. As an illustrative example, the steady-state viscosity η at zero-shear-rate is calculated. The predicted dependence of η on molecular weight and concentration agrees fairly well with experiments.     

Laser-induced fluorescence study of fast desorption of ground-state K atoms from potassium halides excited by synchrotron radiation

The nanosecond desorption of ground-state K atoms from potassium halides was investigated for the first time using a laser-induced fluorescence method with synchrotron radiation and laser pulses. It was found that the desorption consists of a nanosecond component and a slow one of > 180 ns response time. The fast desorption is several orders of magnitude faster than existing results for the time response of ground-state alkali desorption. Therefore, the fast desorption of ground-state alkali atoms cannot be interpreted in terms of the existing mechanisms based on thermal processes and requires a new desorption model. We suggest that the lattice instability due to electronic excitation in the surface layer may play an important role in the fast desorption of ground-state alkali atoms.     

Modified Newton methods for solving a semismooth reformulation of monotone complementarity problems

In this paper, we propose a Newton-type method for solving a semismooth reformulation of monotone complementarity problems. In this method, a direction-finding subproblem, which is a system of linear equations, is uniquely solvable at each iteration. Moreover, the obtained search direction always affords a direction of sufficient decrease for the merit function defined as the squared residual for the semismooth equation equivalent to the complementarity problem. We show that the algorithm is globally convergent under some mild assumptions. Next, by slightly modifying the direction-finding problem, we propose another Newton-type method, which may be considered a restricted version of the first algorithm. We show that this algorithm has a superlinear, or possibly quadratic, rate of convergence under suitable assumptions. Finally, some numerical results are presented. Supported by Research Fellowships of the Japan Society for the Promotion of Science for Young Scientists. Supported in part by the Scientific Research Grant-in-Aid from the Ministry of Education, Science and Culture, Japan.