The dissociation energies D0″ have been measured for GaF, InF, and TlF using high-temperature mass-spectrometric techniques. These results, along with those from previous studies, yield D0″=180±3, 159±3, 138±3.5, 121±3.5, and 101±3.5 kcal/mole for BF, AlF, GaF, InF, and TlF, respectively. Comparison of D0″ thus obtained with that derived from Birge—Sponer extrapolation of the A 1Π state indicates that for all these molecules the spectroscopically derived dissociation energies are higher than the thermochemical values. It is suggested that the difference may be due to a potential maximum in the A 1Π states BF, AlF, GaF, and InF. A maximum is also suggested for the a 3Π1 state of TlF. The appearance potentials of these monofluorides were measured and were found to be 11.5±0.4, 9.5±0.5, 10.6±0.4, 9.6±0.5, and 11.2±0.5 eV for BF+, AlF+, GaF+, InF+, and TlF+, respectively. The dissociation energies and the appearance potentials are briefly discussed in terms of the molecular states of the respective molecules.

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This paper argues that knowledge-based systems are an appropriate tool for the diagnosis of faults in complex devices and that both deep and shallow knowledge have their part to play in this process. The successful implementation and evaluation of the two diagnostic knowledge-based systems, named DIPLOMA and MIDAS, have shown that such systems are an appropriate tool for the diagnosis of faults in complex hydromechanical devices and that they make a beneficial contribution to the business performance of the host organization. Furthermore, it has been demonstrated that the most effective and comprehensive knowledge-based approach to fault diagnosis is one that incorporates both deep and shallow knowledge, so that the distinctive advantages of each can be realized in a single application.

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