Incident-angle dependence of the sensitivity of second-harmonic generation of an oxacyanine dye in an LB film.

The second-harmonic generation of a cyanine dye in an LB film was investigated by varying the incident angle of the excitation laser. There was a clear dependence on the incident angle, which was simulated by a simple model. Thus, a highly sensitive determination should be carried out at such an angle where the efficiency of the second-harmonic generation shows its maximum.     

Mössbauer and NMR studies of iron-carbon martensite

The atomic arrangements in Fe-C martensite, especially the interstitial carbon positions have been discussed utilizing⁵⁷Fe Mössbauer spectroscopy and¹³C and⁵⁷Fe spin-echo NMR measurements. The experimental result is well explained by the model of two interstices occupancy of carbon in the bct martensite. Especially, the spin-echo spectra by¹³C nuclei showed that two main lines first appear and clear satellite lines gradually rise during the aging at 323K, suggesting the carbon jumps from the tetrahedral to the octahedral interstices and further movements to form a local ordered arrangement.     

Homogeneous two-manifolds with an invariant two-form

We study a 2-dimensional manifold that admits a homogeneous action of a 3-dimensional Lie group G, and has a 2-form invariant under G. We show that such a manifold can be realized as a surface in the affine 3-space, and list such realizations.      

A characterization of isotropic immersions by extrinsic shapes of smooth curves

In this paper we show that an isometric immersion is isotropic in the sense of O'Neill if and only if it preserves logarithmic derivatives of first geodesic curvatures of some curves.     

Structure of commelinin,a blue complex pigment from the blue flowers of Commelina communis

The X-ray crystal structure of natural commelinin is investigated. The results demonstrate that commelinin is a tetranuclear (4 Mg²⁺) metal complex, in which two Mg²⁺ ions chelate to six anthocyanin molecules, while the other two Mg²⁺ ions bind to six flavone molecules, stabilizing the commelinin complex, a new type of supramolecular complex.     

Kinetics of hydrogen abstraction reaction between trifluoromethyl formate and OH radical: A theoretical investigation

Kinetics and mechanism of the hydrogen abstraction reaction between trifluoromethyl formate, CF₃OCHO, and OH radical have been investigated by using ab initio molecular orbital theory up to G2(MP2) level. The hydrogen abstraction rate constant has been calculated for the first time over a temperature range of 250–450 K by using standard transition state theory including the tunneling correction. Arrhenius parameters of the reaction have been estimated from the temperature dependence of the calculated rate constant. The calculated value for the rate constant (2.0 × 10^?14 cm³ molecule^?1 s^?1) at 298 K is found to be in very good agreement with the recent experimental results. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 34: 500–507, 2002