This report describes work to conduct several investigations of thin-film polycrystalline solar cells. (1) An analysis of high-efficiency solar cells fabricated at the University of South Florida showed significant reduction in forward recombination current, and the cells were stable over a 3-month test period. (2) Transient voltage effects were documented in a large number of polycrystalline cells and were attributed to long-lived trapping states sensitive to voltage changes near one-half open-circuit voltage. (3) Collection efficiency and its voltage dependence were carefully calculated. The typical effect on photocurrent at operating voltages is about 2% for CuInSe{sub 2}, and less for other cells.

Assignment of the vibrational modes Of Os{sub 2}(CO){sub 8}(CHCH{sub 3}) and Os(CO){sub 4}(C{sub 2}H{sub 4)} has given fingerprint vibrational spectra for the following species when chemisorbed on metal catalyst surfaces: ethylidene and ethylene bound in a metallacyclopropane mode. The formation and fragmentation of diosmacyclobutanes have been shown to involve slippage of the outgoing olefin onto a single osmium, and associative exchange of the olefin from that site. The incorporation of vinylcyclopropane without rearrangement has confirmed the absence of a diradical intermediate. The anomalous stability of the diosmacyclobutane derived from trans-2-butene has proven due to greater destabilization (by the substituent methyls) of the slipped intermediate than of the ground state. Reaction of an osmacyclobutane with 1,3- or 1,2-dienes (allenes) gives 1,2 rather than 1,4 addition to the diosmium unit. Treatment of Os(CO){sub 4}(C{sub 2}H{sub 4}) with triflic acid results in the formation of Os(CO){sub 4}(C{sub 2}H{sub 5})OTf. The authors have found that the reaction of an aryl iodine(III) reagent with propargyl stannanes or silanes results in o-iodo propargyl arenes.

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The main thrust of this work was directed to the task of determining the thermodynamic behavior of condensed solids and fluids containing simple molecules. Properties calculated include specific heats, equations of state, compressibilities, sound velocities, virial coefficients, viscosities, and thermal expansion. In addition, details of the structural, orientational, and magnetic phase transitions were determined. Dynamical quantities calculated include the lattice, libron, and vibron mode frequencies at various pressures and temperatures. Also, we developed new techniques required to meet our objectives. One was a method for accurately calculating the Gibbs free energy of various phases. Another is the multiple-histogram Monte Carlo which can dramatically reduce computing time and can provide a continuous map of thermodynamic averages over a range of some thermodynamical variable.

The attached reports and proposal summarize the work to date for the revised Ultrasonic Resonance Interferometry system. The most recent set of experiments, to determine the accuracy of the implementation of a new calibration curve to account for the variation of the wave speed with temperature, were never completed due to lack of funding. The general focus of the ongoing work, outlined in the weekly reports, had been improvements in accuracy of the measurement system using software modifications. The future focus of the project, as outlined in the attached proposal, was to incorporate a thermal conductivity probe with the ultrasonic measurement system to allow measurement of fluids which have a bimodal wavespeed vs. molarity relation.