This report documents the library of thermodynamic data used with the NASA Glenn computer program CEA (Chemical Equilibrium with Applications). This library, containing data for over 2000 solid, liquid, and gaseous chemical species for temperatures ranging from 200 to 20,000 K, is available for use with other computer codes as well. The data are expressed as least-squares coefficients to a seven-term functional form for C((sup o)(sub p)) (T) / R with integration constants for H (sup o) (T) / RT and S(sup o) (T) / R. The NASA Glenn computer program PAC (Properties and Coefficients) was used to calculate thermodynamic functions and to generate the least-squares coefficients. PAC input was taken from a variety of sources. A complete listing of the database is given along with a summary of thermodynamic properties at 0 and 298.15 K.

NASA Glenn Coefficients for Calculating Thermodynamic Properties of Individual Species

Presentation du probleme et des methodes theoriques de calcul des intensites. Application aux systemes moleculaires XY 2

Overtone frequencies and intensities in the local mode picture

Rapid formation of Jupiter by diffusive redistribution of water vapor in the solar nebula

A computational approach to the direct configuration interaction method is described The method is formulated using the calculus of the generators of the unitary group The simple structure of the generator matrices within the harmonic excitation level scheme is exploited to give a computational method that is competitive with traditional approaches A new scheme for basis set truncation in the case of partial configuration interaction is devised employing orbital populations It is also shown that the block structure of the generator matrices leads to the definition of a new order parameter for perturbation methods which is both effective and convenient

Application of unitary group methods to configuration interaction calculations

Theories of intramolecular vibrational energy transfer

A rotational analog of the vibrational potential energy surface is introduced for describing the rotational fine structure of polyatomic molecules. Classical trajectories on rotational energy (RE) surfaces are related to quantum rotational eigenvalue structure. Interpretation of RE surfaces shows how very different types of molecules may undergo dynamical symmetry breaking and a corresponding clustering of rotational energy sublevels for high angular momentum (J>10). Cluster splitting and spacing are calculated using semiclassical quantization methods. Some consequences of dynamical symmetry breaking such as mixing of nuclear spin species are discussed qualitatively.

Rotational energy surfaces and high‐J eigenvalue structure of polyatomic molecules

Cw stimulated Raman gain spectroscopy of the ν1 fundamental of methane

We give a quantitative analysis for the clusters of octahedral terms which appear in the high resolution rotational spectra of SF6 for large angular momentum. We derive approximate expressions for the cluster energies and the splittings within each cluster which obviate the diagonalization of the octahedral deformation potential.

Orbital level splitting in octahedral symmetry and SF6 rotational spectra. II. Quantitative treatment of high J levels

The theory of transformation relations between states of Born Oppenheimer and weak coupling approximations is developed for polyatomic molecules. The relations are a generalization of frame transformation relations used by Chang and Fano for symmetric-top molecules, and they lead to a more convenient symmetry labeling system than was previously available. A key internal symmetry label (named ''soul'') is defined so that it remains a constant label for frame transformation relations, and is conserved during vibronic transitions, ionization, and even dissociation provided the nuclear spin--rotation interaction is relatively small. Various nomograms, graphs, and tableaus associated with the soul label make it easy to predict and visualize the form of many types of complex high-resolution spectra. Simplified procedures are given for obtaining selection rules, statistical weights, and matrix elements of multipole operators for common molecules having various point symmetries. Simplifications of computational theory using the new level cluster bases for high J are discussed.

Frame transformation relations and multipole transitions in symmetric polyatomic-molecules

High‐resolution spectra of the infrared‐active stretching fundamental ν3 of 238UF6 have been obtained between 620.6 and 633.5 cm−1 using tunable semiconductor diode lasers. Interference from hot bands was suppressed by cooling the UF6 in a supersonic expansion, and useful monomer concentrations were produced with effective temperatures of <100 K. Portions of the band from P(77) to R(66) are illustrated. All transitions from the vibrational ground state have been assigned, and the Q branch has been fully analyzed. A total of 43 line frequencies and 110 frequency differences extending in J to P(77), Q(91), and R(67) has been used to fit seven spectroscopic constants. The ground‐ and excited‐state values of the rotational constant B could be individually determined, and the U–F bond length in the ground vibrational state is r0=1.9962±0.0007 A. The Q branch of 235UF6 has also been analyzed and the 235UF6–238UF6 ν3 isotope shift measured to be 0.603 79±0.000 17 cm−1. The isotope shift and the Coriolis constant...

Chris W. Patterson

Papers

Rotational energy surfaces and high‐J eigenvalue structure of polyatomic molecules

Cw stimulated Raman gain spectroscopy of the ν1 fundamental of methane

Orbital level splitting in octahedral symmetry and SF6 rotational spectra. II. Quantitative treatment of high J levels

Frame transformation relations and multipole transitions in symmetric polyatomic-molecules

Measurement and analysis of the infrared‐active stretching fundamental (ν3) of UF6