Addition of singlet oxygen to aromatic compounds has attracted much attention for utilization in the photochromic systems. The regiospecificity accompanied with the addition of oxygen is altered by introduction of functional groups and it is difficult to determine where the addition occurs. We prepared single crystals of the endoperoxide of anthra[1, 9-bc:4, 10-b'c']dichromene(1) and determined the positions of singlet oxygen addition by X-ray crystallographic analysis. The positions are 9- and 10-positions of anthracene moieties but not the 1- and 4-positions, coincided with the prediction from the coefficients of highest occupied molecular orbital calculated by AM1 or PM3 procedure

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A method for the simultaneous determination of polycyclic aromatic hydrocarbons (PAHs) was developed by means of fluorometric analysis combined with partial least squares regression (PLS) analysis. Fluorescence spectra (Ex=305nm, Em=330-520nm) of twenty one synthetic solutions, which contain five sorts of PAH (10^-2-10^-1 μ g cm^-3) in n-hexane, were converted into ASCII data set. These were imported into a microcomputer and modified to make a regression model by employing PLS software. Newly prepared mixtures of all five PAHs (Benzo [a] pyrene, Perylene, Fluoranthene, Pyrene and Chrysene) were analyzed simultaneously using this model. The results predicted were in good agreement with the real data.

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There are many software in the field of chemical education. However, it was found, via student questionnaires, that these software have some defects, for example students like to see more realistic graphics rather than the computer graphics, and teachers also like to have a more intractive approach in their classes. We have developed new type CAI software to solve these difficulties by using a new technique which enables us to use different multimedia sources as part of original CAI programs.
These multimedia software will hopefully improve the use of CAI programs in chemical education. In particular, we edited the video movie into a short interval (a few minutes) file and used it in CAI programs as an original and novel method.

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The molecular graphic program 'Modrast-E' for Sun workstation was extended in its function. In the cutting function, three different styles of display, that is, ball and stick model clipped by one or two plane (s), clipped space filling model combined with ball and stick model, and space-filling model clipped by cylinder, were newly developed. As to the graphical user interface, Modrast-E was also improved. The atoms which define a cutting plane oran axis of rotation are able to be specified directly by pointing the displayed atom on the screen with the mouse.
This program is available through an anonymous FTP site of The Chemical Software Society Japan. (http://cssj.chem.sci.hiroshima-u.ac.jp/ftp/indexe.html)

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Recently, the total energies of metals have been calculated by the embedded atom method (EAM) which deals with interatomic binding energies based on many body interactions. Since the development of the personal computer makes it possible to execute the EAM calculation in a short time, the surface energy on various planes of f. c.c. metals (Al, Cu, Ag, Au, Ni, Pd and Pt) was calculated by the EAM. It was found by the calculation that the relative surface energies among these f. c. c. metals were different for each crystal plane, though the calculation based on two body interactions could not reveal such differences. The surface energies on the (111) plane of gold and platinum were relatively lower than the values calculated for other metals. According to the prediction derived from this result, the 2 x 1 missing row reconstructions on the (110) surface of gold and platinum were displayed by the calculation of the most stable surface structure. This software package was developed using the Borland C++ compiler and can be executed on the MS-Windows system.

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