A computer‐operated spectrograph was recently built at Okazaki, Japan. Different specimens can be placed on a horseshoe‐shaped focal curve (10 m long) covering a wavelength range of 250 to 1000 nm so they can be irradiated simultaneously. The linear dispersion is about 0.8 nm/cm. The photon fluence rate on the focal curve is 5 x 1015. photons x cm‐2 x s‐1 at 300nm and 1 x 1016 photons x cm‐2 x s‐1 at 600 and at 900 nm. The spectral half width is 5.5 nm or less on the focal curve. The stray light content is about 10‐5 of the main peak at the peak wavelength ± 100 nm. Specimens are set in microcomputer‐controlled threshold boxes so that wavelengths, photon fluence rates, photon fluences and timing of irradiations are controlled automatically according to a pre‐programmed schedule. An optical fiber system is also provided for remote irradiations.

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Electron temperature fluctuations are measured with a rotatable triple probe in PANTA. Effects of fluctuation phase are cancelled by aligning the probe pins in the propagation direction of fluctuations. Evaluated electron temperature fluctuations normalized by average electron temperature are much smaller than normalized density fluctuations and normalized floating potential fluctuations in low electron temperature PANTA plasma. Additionally conditional sampling technique is applied to a single probe measurement.

Carbon-13 NMR and UV absorption spectra have been obtained for a//-Z/-anj-7V-retinylidene-«-butylamine and its acid-addition salts as an analogue of the Schiffs base linkage compound in visual pigment. Carbon-13 chemical shift changes on going from aZZ-rrans-ZV-retinylidene-n-butylamine to its acid-addition salts are observed. The -electron density and -bond order of polyene chain were calculated for these compounds by CNDO/2-MO method. The change in carbon-13 chemical shift was found to correlate quite well with that in -electron density. It was deduced that the large red shift of UV absorption maximum by N protonation of a/Z-Zz-tinj-ZV-retinylidene-zi-butylamine may be mainly due to the decrease of the degree of bond alternation and the delocalization of the positive charge in conjugated polyene chain. The effect of solvent (methanol and carbon tetrachloride) on the UV bathochromic shift and carbon-13 chemical shift was also discussed briefly.

The currents through polyethylene single crystals have been measured as functions of voltage and temperature between 200°K and 400°K. The negative resistance phenomena were sometimes observed when thin wire electrodes were used for measuring the current through polyethylene single crystals of 70–300 Å thickness, but their behaviors were different from those described by Roggen. In the case of vacuum evaporated electrodes, however, such phenomenon was not observed. Similar measurements have been done with polyethylene thin films formed by vacuum evaporation. In this case, the negative resistance similar to that described by Hickmott was sometimes observed. Changes of specific resistance were closely related with the change of crystal thickness in thinner crystals, and the electron transport mechanism was discussed quantitatively with simple theoretical expressions of tunneling effect and Schottky emission.

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The temporal characterization of a femtosecond laser pulse in the deep ultraviolet region using an interferometric autocorrelation scheme is demonstrated. Two-photon ionization of a molecule in a time-of-flight mass spectrometer was used as a nonlinear detector to obtain an autocorrelation trace. This setup proved useful in not only providing a temporal characterization of a pulse but also investigating the ultrafast dynamics of photochemical processes.

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