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High resolution infrared emission spectra of aluminum monohydride and monodeuteride have been recorded. Gaseous AlH and AlD were generated by reacting molten aluminum metal with hydrogen and deuterium gas. Approximately 265 AlH lines with v=1→0 to v=5→4 and 470 AlD lines with v=1→0 to v=7→6 are reported. Dunham Yij constants were obtained by fitting the data of each isotopomer separately to the Dunham energy level expression while mass-reduced Dunham Uij constants were obtained from a combined fit of all isotopomer data. A second set of Dunham Uij constants was obtained from a fit where Uij’s with j<2 were treated as adjustable parameters and all remaining Uij’s fixed to values that satisfy the constraints imposed by the Dunham model. Finally, an effective Born–Oppenheimer potential was determined by fitting all the data directly to the eigenvalues of the radial Schrödinger equation containing a parametrized potential function. [ABSTRACT FROM AUTHOR]

The high resolution infrared emission spectra of gallium hydride and gallium deuteride have been recorded with a Fourier transform spectrometer. There were 1045 lines observed including those from the v=1→0 to v=7→6 bands for the 69GaD and 71GaD species and v=1→0 to v=4→3 bands for the 69GaH and 71GaH species. Dunham Yij’s for each isotopomer were obtained by fitting the data set of each isotopomer separately to the Dunham energy levels of the X 1Σ+ electronic ground state. The mass-reduced Dunham Uij’s were determined using two independent methods. In the first fit the Uij’s constants were determined by the traditional method where all the constants were treated as adjustable parameters and determined statistically. In the second fit the Uij’s which satisfied the condition j<2 were treated as adjustable parameters and the remaining constants were fixed by constraints imposed by the Dunham model. In order to predict the positions of transitions with v’s and J’s much higher than those observed the entire data set was fit directly to the eigenvalues of the Schrödinger equation containing a parameterized internuclear potential energy function. [ABSTRACT FROM AUTHOR]

The high resolution infrared emission spectrum of aluminum monochloride has been recorded with a Fourier transform spectrometer. A total of 1747 rovibrational transitions, v=1→0 to v=8→7, for the most abundant isotopomer 27Al35Cl and 708, v=1→0 to v=4→3, for the least abundant isotopomer 27Al37Cl have been assigned. This new set of infrared data was combined with existing microwave and millimeter-wave data to refine the Dunham Yij constants for the X 1Σ+ electronic ground state. In addition two sets of mass-reduced Dunham Uij constants have been determined from separate fits. In the first fit all of the Uij constants that could be statistically determined were treated as adjustable parameters. In the second fit only the constants satisfying the condition j<2 were treated as adjustable parameters while the values for the remaining constants were fixed to constraints imposed by the Dunham model. Finally, in order to fully utilize the information provided by this extensive data set in an attempt to improve the prediction of energies for higher lying v, J levels of the X 1Σ+ state, the combined data set, consisting of microwave, millimeter, and infrared (IR) data were fitted directly to the eigenvalues of the Schrödinger equation containing a parametrized internuclear potential energy function. [ABSTRACT FROM AUTHOR]

Crystal field theory has been used to identify and locate the energy levels of low-lying (below 10 000 cm-1) states of the rare earth monoxides. These states were then used to calculate the thermal functions, which were, in turn, used to derive accurate dissociation energies of the rare earth monoxides. These newly derived dissociation energies are discussed in terms of a model related to the promotion energies for 4f n+15d0→4f n5d1. [ABSTRACT FROM AUTHOR]

Sub-Doppler Zeeman spectra of several low-J rotational lines in 0–0 bands of CeO[16.5]2–X12, [16.5]4–X23, [18.4]4–X34, and [19.3]3–X43 systems have been recorded by intermodulated fluorescence spectroscopy. Electronic g values for the four lower states [the Ω=Ja states of the Ce+2(4 f 6s)O-2] superconfiguration obtained from Zeeman splittings of low-J lines at magnetic fields up to 1100 G, are found to agree with g values calculated from the eigenvectors of a ligand field effective Hamiltonian. The present results demonstrate the capability of the ligand field model to predict electronic properties in addition to energies and illustrate the value of the Zeeman effect for uncovering the atomic–ion quantum numbers which are not normally specified for molecules in the strong spin-orbit [Hund’s case (c)] limit. [ABSTRACT FROM AUTHOR]