Fred L. Voelz

Substituted Methanes. XXVI. Raman and Infrared Spectral Data, Assignments, Potential Constants, and Thermodynamic Properties for CHBrCl2 and CDBrCl2

Raman displacements, semiquantitative relative intensities, and quantitative depolarization factors for liquid bromodichloromethane and deuterobromodichloromethane, as well as infrared wave numbers and percent transmission curves for both the liquid and gas in the region 400—4000K (K = kaysers = cm—1), were obtained and compared with previous data. Assignments were made for both molecules and a reasonable set of potential constants was determined by use of Wilsons FG matrix method. The heat content, free energy, entropy, and heat capacity were calculated for 12 temperatures from 100° to 1000°K.

Substituted Methanes. XVII.* Vibrational Spectra, Potential Constants, and Calculated Thermodynamic Properties of Diiodomethane

Raman displacements, semiquantitative relative intensities, quantitative depolarization factors, and wave numbers for the infrared bands in the region 400–3800 cm−1 have been obtained for liquid CH2I2. A normal coordinate treatment was carried out, and a reasonable set of potential constants was determined, using the most general quadratic potential energy function. Assignments were made for all observed Raman and infrared bands. The heat content, free energy, entropy, and heat capacity at constant pressure were calculated for 12 temperatures from 100° to 1000°K.

Substituted Methanes. IX. Raman and Infrared Spectra, Assignments, Potential Constants, and Calculated Thermodynamic Properties for CHClBr2 and CDClBr2

Raman displacements, semiquantitative relative intensities, and quantitative depolarization factors for liquid chlorodibromomethane and deuterochlorodibromomethane, and infrared wave numbers and percent transmission curves for both the liquid and gaseous states in the region 400–4300 cm−1 were obtained and compared with previous data. A normal coordinate treatment (Wilson FG matrix method) was carried out, and a consistent set of potential constants for both molecules was determined, using a potential energy function containing all possible 2nd degree terms. Assignments were made for all observed bands. The heat content, free energy, entropy, and heat capacity at constant pressure were calculated for 12 temperatures from 100° to 1000°K.

Substituted Methanes. XVIII. Vibrational Spectra of C13H3I

Raman (liquid) and infrared (liquid and gas, with KBr and NaCl prisms) spectra have been obtained for two mixtures of C13H3I (9.3 and 61 atom percent) and C12H3I, and from these the vibrational spectrum of C13H3I has been deduced. In the Raman spectrum, only v3(a1)—the C–I stretching frequency—could be resolved from the C12H3I lines; the isotopic shift was — 17.7±0.5 cm—1. In the infrared spectrum (gas), five isotopic shifts were obtained; they were: v1(a1) — 10±3, v2(a1) — 5.5±1.0, v3(a1) — 16.1±1.0, v5(e) — 4.4±0.8, and v6(e) — 3.7±0.3 cm—1. For the remaining fundamental, v4(e), the shift was obtained by use of the Redlich‐Teller product rule; the value was — 9.4±2.3 cm—1. Analysis of the perpendicular bands yielded, with the aid of microwave data, values of the rotational constants, Coriolis interaction constants, and band origins for the v6(e), v5(e), and v4(e) bands of C12H3I and C13H3I, though the values for the v4(e) band of C13H3I are incomplete and are only estimated values since the sub‐bands we...

Substituted Methanes. XXII. Infrared Spectra of CHBrF2, and Potential Constants and Calculated Thermodynamic Properties of CHBrF2 and CDBrF2

The near infrared spectrum of gaseous bromodifluoromethane was obtained using a Perkin‐Elmer Model 21 Spectrometer equipped with a NaCl prism. A set of potential constants was determined for CHBrF2 by means of the Wilson FG matrix method, using a potential energy function with all possible second degree terms. The same potential constants were used to calculate the fundamentals of CDBrF2. Finally the heat content, free energy, entropy, and heat capacity were calculated for 12 temperatures from 100 to 1000°K, for the ideal gaseous state at 1 atmos pressure, using the observed fundamentals for CHBrF2 and the calculated ones for CDBrF2.

Force Constants and Calculated Thermodynamic Properties for SiF4

Using observed fundamental frequencies and the Wilson FG matrix method, sets of force constants for SiF4 have been determined using the most general second degree potential energy function. While no unique set of force constants can be given, limits are set for the force constants. Also the calculations indicate that if the Si–F bond interaction constant is ignored, too high a value for the Si–F bond stretching force constant results. Finally, the heat content, free energy, entropy, and heat capacity for the ideal gaseous state at 1 atmos pressure were calculated for 11 temperatures ranging from 100–1000°K, using a rigid rotator, harmonic oscillator approximation.

Substituted Methanes. XI. Potential Constants for CBr3Cl

A new set of potential constants has been obtained for CBr3Cl using the Wilson FG matrix method and a potential energy function containing all possible second degree terms. These constants are in better agreement with those determined for CBr2Cl2, CBr2ClH, CBr2ClD, and CCl3Br than the set given previously.

Raman and Infrared Spectra and Structure of 2,6‐Dioxaspiro (3,3)heptane

The Raman spectrum of 2,6‐dioxaspiro (3,3)heptane in the molten state and infrared spectra of CS2 and CCl4 solutions have been investigated. The polarization of the Raman lines of the liquid also has been studied. The results indicate a symmetry D2d for the molecule. The appearance of two extra strongly polarized Raman lines near the 2874K (kayser, cm—1) line, which corresponds to the totally symmetric C–H stretching oscillation, has been accounted for by assuming Fermi resonance between overtones of C–H bending vibrations and the symmetric C–H stretching mode.