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A relational database management system has been implemented on the Caltech millimeter-wave array for both real-time astronomical and engineering data and post-processing calibration and analysis. This system provides high storage efficiency for the data and on-line access to data from multiple observing seasons. The ability to access easily the full database enables more accurate calibration of the raw data and greatly facilitates the calibration process. In this article we describe both the structure of the millimeter-array database and the implementation of a data analysis program, both of which make extensive use of Sybase, a commercial database management system with application development software. This use of relational database technology in real-time astronomical data storage and calibration may serve as a prototype for similar systems at other observatories.

These cross sections were measured by the process of passing a deuteron beam into a thin gas target contained behind a thin window of evaporated silicon monoxide. The energy loss in the window was measured by a deceleration technique. Charged particles from the reactions were observed at 90° in the laboratory system with proportional counters. Some results are as follows: for the reaction D(d,p)T, by use of the angular distribution reported by Wenzel and Whaling, the total cross section o-is 15.4 mb with a probable error of 3.2 percent at 100-kev incident deuteron energy; cr=0.629 mb±5 percent at 25 kev. For the reaction D(d,n)JIe z , o-=15.2 mb±3.2 percent at 100 kev;

Integrated intensities have been measured for O-H stretching vibrational bands, including fundamentals and the first three overtones for methanol, ethanol, 1-propanol, 2-propanol, tert-butyl alcohol, 2,2,2-trifluoroethanol, nitric acid, and acetic acid. Fundamental band strengths are seen to increase with the electronegativity of the adjacent substituent, though directly analogous trends for overtones are less apparent. However, substituent electronegativity does parallel the proportional decrease in overtone intensity, relative to the corresponding fundamental. In addition, the intensities have been modeled using a two-parameter, linear-exponential dipole moment function. The agreement between observed and calculated intensities is fair, but the overall shapes of the fitted dipole moment functions also parallel the inductive nature of the substituent. Some tentative rationale for the observed intensity trends is offered, but definitive claims cannot be made without further investigation. The current results are finally compared to a few studies of C-H-containing compounds, and differences in the respective intensity data are discussed.

We have conducted an extensive computational study of the structure, bonding, B−N potential energy curve, and vibrational frequencies of CH3CN−BF3, using MP2, B3LYP, and BWP91 methods with basis sets ranging from STO-3G to aug-cc-pVQZ. Two types of minimum energy structures were found; one group with B−N distances near 1.8 Å, another with distances near 2.3 Å. In most cases, longer bond length structures were found with basis sets lacking diffuse functions, whereas shorter bond length structures were found when these functions were included. The exception is the largest basis set (aug-cc-pVQZ), for which the equilibrium B−N distance was found to be 2.315 Å. Potential energy curves calculated for the B−N stretching coordinate are found to be remarkably flat, and this results from the occurrence of two competing minima corresponding to the two types of minimum energy structures. At the B3LYP/aug-cc-pVQZ level, an extremely flat region occurs near 1.93 Å on the B−N potential curve, which lies about 0.2 kcal/mol above the global minimum after accounting for the effects of basis set super position error (BSSE) and zero-point vibrational energy (ZPE). The results are nearly converged with respect to basis set at the B3LYP/aug-cc-pVQZ level; further attempts at increasing the size of the basis set were not successful. An AIM analysis indicates that the two minima in the B−N potential arise from distinctly different interactions, the longer being primarily an electrostatic interaction, the inner being a partial covalent bond. Given the flat, asymmetric nature of the potential, it is very likely that the equilibrium and vibrationally averaged structures differ significantly due to large amplitude motion in the intermolecular B−N stretching mode. Furthermore, a comparison of experimental and calculated vibrational frequencies leads to the tentative conclusion that the B−N distance is significantly shorter in an argon matrix than in the gas phase.