Variable axis lens of mixed electrostatic and magnetic fields and its application in electron-beam lithography systems J.Accuracy and resolution of scanning electron microscopy and an electron-beam lithography system directly depend on beam diameter; it should be monitored and tuned frequently. A technique is described to determine beam size using an automatic procedure. In the developed method, a specially designed and fabricated test pattern is scanned using an e-beam. A spectrum of the signal is analyzed; beam diameter is automatically determined using a software program. Results of design, fabrication, and analysis of the beam calibration test pattern are presented.

Using an exciton as a carrier was examined as a possible solution to the problem of signal transmission between molecular logic gates. Tetrathiafulvalene chain was chosen as a model for...

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A simplified form of the Bixon-Jortner-Plotnikov (BJP) method is derived for calculation of internal conversion (IC) rate in a symmetrical molecule. The rate is a sum of contributions from individual transitions between vibronic states. For each transition, vibrational modes are divided into two groups, the promoting (one or two modes per electronic transition) and the surrounding ones. In the case of the non-totally symmetric transition in a symmetric molecule, the overwhelming majority of transitions do not contribute to the overall rate. Moreover, the promoting and surrounding modes belong to different symmetry representations and can be separated. It is proposed to deal with the promoting modes directly, while approximating the effect of the surrounding modes by a Pekarian function. The method was tested on polyacenes and it was shown that the calculated IC rates are in agreement with the experimental ones. The simplified method can be applied for calculating the rates of non-totally symmetric transition in a symmetric molecule, if its point symmetry group does not change after transition.

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