Volume 7, Issue 4, October 1978
Index of content:
7(1978); http://dx.doi.org/10.1063/1.555584View Description Hide Description
Recent experimental measurements of atomic electron binding energies, 1s to 6p 3/2, for certain of the transuranic elements are incorporated into interpolation and extrapolation procedures yielding new recommendations for the electron binding energies from Z=84 to 103.
7(1978); http://dx.doi.org/10.1063/1.555585View Description Hide Description
The available molecular parameters, fundamental frequencies, and enthalpies of formation at 298.15K (ΔH f ° (298) for halomethanes of the type CH4−(a+b+c+d)F a Cl b Br c I d have been critically evaluated and recommended values selected. Molecular parameters and ΔH f ° (298) for some halomethanes have been estimated as the experimental values for these compounds are not available. This information has been utilized to calculate the ideal gas thermodynamicpropertiesC p °, S °, H °−H ° 0,−(G °−H 0 °)/T, ΔH f °, ΔG f °, and logK f from 0 to 1500 K and at a pressure of one atmosphere using the rigid rotor‐harmonic oscillator approximation for the following compounds: CH2FBr, CH2ClBr, CH2CH, CH2BrI, CHF2Br, CHFClBr, CHFBr2, CHCl2Br, CHClBr2, CF3Br, CF3I, CF2ClBr, CF2Br2, , CF2I2, CFCl2Br, CFClBr2, CFBr3, CCl2Br, CCl3I, CCl2Br2, CClBr3.
7(1978); http://dx.doi.org/10.1063/1.555586View Description Hide Description
The results of a critical review of vibrational data, their assignments, and force field constants of polyethylene and the related homologous series of n‐alkanes are presented. The vibrational frequencies derived from Raman spectroscopy,infrared spectroscopy, and neutron inelastic scattering were collected from the literature. We have reviewed the vibrational band assignments starting from the comprehensive treatment of the n‐alkanes by Schachtschneider and Snyder [1,2]1 and including subsequent reassignments. Theoretical calculations of the vibrational frequencies were reviewed with emphasis on the various models used for molecular structure and force fields. Lattice dynamical calculations of polyethylene were performed using a valence force field for intramolecular interactions and a force field derived from a nonbonded atom‐atom potential function for intermolecular interactions. The molecular and lattice structural parameters were taken from x‐ray and neutron diffraction studies of polyethylene and selected n‐alkanes. A refinement procedure was carried out by the method of least squares on intramolecular force field constants and on parameters of a phenomenological nonbonded atom‐atom potential energy function. The resulting force field constants and associated standard deviations are presented.
7(1978); http://dx.doi.org/10.1063/1.555587View Description Hide Description
Fundamental vibrational frequencies of 109 molecular forms of 38 polyatomic chain molecules consisting of the CH3, CD3, CH2 CD2, CHD, O, and S groups are given as an extension of tables of molecular vibrational frequencies published in the NSRDS‐NBS publication series and in this journal. On preparing the tables in this part, an approach, different from that in the previous parts, based on the calculations of normal vibration frequencies was adopted. A set of force constants which explains all the frequencies of small molecules for which the assignments had been established was obtained and then the frequencies of larger molecules was calculated and compared with the frequencies observed in the infrared and Raman spectra. The tables provide a convenient source of information for those who require vibrational energy levels and related properties in molecular spectroscopy,thermodynamics,analytical chemistry, and other fields of physics and chemistry.
7(1978); http://dx.doi.org/10.1063/1.555588View Description Hide Description
All of the rotational spectra lines observed and reported in the open literature for 54 triatomic molecules have been tabulated. The isotopic molecular species, assigned quantum numbers, observed frequency, estimated measurementuncertainty and reference are given for each transition reported. In addition to correcting a number of misprints and errors in the literature cited, the spectral lines for approximately 15 molecules have been refit to produce a comprehensive and consistent analysis of all the data extracted from various literature sources. Both measured and predicted transition frequencies are listed for several isotopic forms of HCN, H2O, H2S, OCS, SO2, and O3. The derived molecular properties, such as rotational and centrifugal distortion constants, hyperfine structure constants, electric dipole moments, and rotational g‐factors are listed with one standard deviation uncertainty for all values.