PSDF of log-amplitude scintillation for 7 μm band laser beam with absorption by water vapour

The power spectral density function (PSDF) of the log-amplitude scintillation for an infrared laser beam was measured experimentally. To investigate the contribution of the absorption and the dispersion that cause the scintillation, we chose 16 wavelengths of infrared light and one wavelength of visible light. It is found that the spectral density of scintillation for the infrared beam does not agree with that for the visible beam, as predicted by Tatarskii's theory in the low-frequency region below 1 Hz. This disagreement between the experiment and the theory in the low-frequency region should be attributed to water vapour absorption.     

Momentum distribution of Hückel π electrons

The momentum distribution and related physical properties are examined for π molecular orbitals (MOs) of a conjugated hydrocarbon system obtained by the empirical Hückel method. Several general rules are derived and the momentum-space aspect of the Hückel π electron theory is clarified.     

Energy-density relations in momentum space. III. Variational aspect

A variational formula for the momentum density is derived by using the Hellmann-Feynman theorem and by introducing a reference system whose Hamiltonian differs only in the kinetic energy part from that of the original system. As simple applications of the present results, the reduced mass correction and the relativistic correction for the hydrogen-like atom are discussed.     

A relation between the dirac field of the electron and electromagnetic fields

There is a point of view from which a field governed by the Dirac equation for the electron is the same as a field governed by the Maxwell-Lorentz equations for electromagnetic fields. This observation suggests the possibility that the two sets of equations are of the same origin.     

Stereochemical studies—XXX : Stereoselective synthesis of D-ribose from L-glutamic acid

A new stereoselective synthesis of D-ribose (14) starting from L-glutamic acid (1) is described, by making use of the chiral center of 1 as that at C-4 of 14. Oxidation of methyl 5-O-benzyl-2,3-dideoxy-D-pent-2-enofuranoside (10) with potassium permanganate or osmium tetroxide was shown to occur preferentially from the rear side of the OMe group at C-1.     

Pyrolysis of amines: Infrared spectrum of methyleneimine

Methyleneimine was detected in the gas phase by a moderately high resolution infrared spectrometer as one of the intermediate species produced by a pyrolysis of amines. Observed vibrational frequencies of some isotopic derivatives have been combined with the ab initio values to reach a most reliable force constants set. Some other spectroscopic parameters, involving geometrical parameters and dipole moment derivatives, have also been calculated ab initio and compared with the observation. Its half-life in our experimental apparatus was about 10 min, which is much longer than the previously reported values, 0.1 or 10 sec.     

Field Analysis of Pillbox Resonator with Radiation Loss Utilizing Finite-Element Beam Propagation Method Formulation

To deal with the radiation from an axially symmetric pillbox resonator embedded in LiNbO₃ substrate, an eigenvalue equation is derived from the expression of the finite-element beam propagation method in a cylindrical coordinate system. By solving the eigenvalue equation iteratively, the field distributions and the angular phase constants of the pillbox resonator are evaluated. The iterative scheme of solving the eigenvalue equation is an extension of our previous direct solution method which was described for a lossless case. The results obtained by this method are compared with those obtained analytically, and excellent agreement is found.