Knowledge Bank

A program for the critical evaluation of microwave spectra of molecules of astrophysical interest has been started as part of the microwave spectral data center at the National Bureau of Standards. For each molecule studied, the literature is surveyed to ensure that the measurements reported are the most recent and most accurate. When possible, the spectra are fit to a theoretical model and the frequencies as of yet unmeasured transitions are predicted. A statistical analysis of the data tests the adequacy of the model and allows uncertainties to be estimated on the predicted spectrum. When necessary, new transitions are measured. The final product is a spectral table containing measured and observed transition frequencies with their associated estimated uncertainties, line strengths and energies of the upper and lower states. Cooperation with other laboratories in both measurement and analysis has allowed a wider range of choice in the molecules studied.