Dielectric constants and pair interactions in polar molecules

A qualitative description of dielectric processes in Pair interactions of polar molecules is presented, discussing such factors as molecular shape and polarizability. The mathematical treatment of these interactions is given, derived from classical electric field theory and statistical mechanics. The dielectric virial equation and the meaning of the dielectric virial coefficients is discussed. Due to the small magnitude of the coefficients, one must make measurements on the gas of the molar volume to one part in 10 4 and of the dielectric constant to one part in 106 to derive values of the second dielectric virial coefficient to within 10%. A general description of the Burnett and modified Burnett expansion techniques is given, with their application to dielectric measurements. A description of the apparatus which has been assembled is given, including the development of an inexpensive pressure measuring system. The electronic methods used for measuring dielectric constants to one part in 106 to 107 are described, along with those for the pressure measuring system. With humble apologies for being less than perfect, but thankful for being no less than human, I dedicate this to all who have cried upon my shoulders, all whose shoulders I have cried upon, and especially VRVA, BSF, EAM and KAMCW

The Microwave Spectra and Molecular Structures of Vinyl Fluoride Ozonide and Vinylidene Fluoride Ozonide.

The rotational spectra of twelve isotopic species of vinyl fluoride ozonide (3-fluoro-1,2,4-trioxolane, I) and seven species of vinylidene fluoride ozonide (3,3-difluoro-1,2,4-trioxolane, II) were assigned. These included all of the possible single-deuterium substituted species of both compounds, five ('18)O substituted species of I and four ('18)O species of II, and the triple-deuterium and both single-('13)C substituted species of I. The structure of I was analysed by both least-squares (r(,o)) and Kraitchman's substitution (r(,s)) methods. The presence of a numberof small coordinates made the r(,s) structure somewhat inaccurate, and the r(,o) structure was chosen as the best of those obtained. Theoverall structure is a five membered ring (FCHOOHCHO) with a(' )conformation intermediate between an O-O twist and an O(peroxy,CH(,2)) envelope, with an axial fluorine substituent. Some of the significant structural parameters are: r(O(,ether)-C(,H)) = 1.426(5) (ANGSTROM); r(O(,e)-C(,F)) = 1.382(10) (ANGSTROM); r(C(,H)-O(,peroxy)) = 1.411(5) (ANGSTROM); r(C(,F)-O(,p)) = 1.382(10) (ANGSTROM); r(O-O) = 1.463(5) (ANGSTROM); r(C-F) = 1.375(5) (ANGSTROM); (ANGLE) C-O-C = 105.3(4)(DEGREES); (ANGLE) O-C(,F)-O = 107.6(4)(DEGREES); (ANGLE) O-C(,H)-O = 101.1(3)(DEGREES); (ANGLE) C(,H)-O-O = 104.6(2)(DEGREES); (ANGLE) C(,F)-O-O = 99.3(3)(DEGREES); (ANGLE) C-O-O-C = 46.0(DEGREES); O-C(,H)-O-O = 40.4(DEGREES); (ANGLE) O-C(,F)-O-O = 35.0(DEGREES); (ANGLE) F-C-O-O = 83.5(DEGREES). The uncertainties represent one st and ard deviation. An insufficient number of isotopic species of II were assigned to permit a complete structural determination by either of the above means. Bartell's method of predicate observables was used in this case, based on the available data, the structure of I, and extrapolated structural trends. The ring conformation of II is very close to a pure O(peroxy,CH(,2)) envelope, with a C-O(,e)-C(,F)-O dihedral angle of only 2 (+OR-) 4(DEGREES). The following structural parameters were obtained: r(O(,e)-C(,H)) = 1.425(25) (ANGSTROM); r(O(,e)-C(,F)) = 1.368(20) (ANGSTROM); r(C(,H)-O(,p)) = 1.404(20) (ANGSTROM); r(C(,F)-O(,p)) = 1.360(25) (ANGSTROM); r(O-O) = 1.467(10) (ANGSTROM); (ANGLE) C-O-C = 103.9(DEGREES); (ANGLE) O-C(,F)-O = 110.5(DEGREES); (ANGLE) O-C(,H)-O = 103.5(DEGREES); (ANGLE) C(,H)-O-O = 99.4(DEGREES); (ANGLE) C(,F)-O-O = 101.8(DEGREES); (ANGLE) F-C-F = 105.1(DEGREES); (ANGLE) C-O-O-C = 42(DEGREES); (ANGLE) F(,axial)-C-O-O = 96(DEGREES). The structures of I and II are both analysed in terms of the anomeric effect. In both molecules this effect is seen (a) by the shortening of the C(,F)-O bonds, (b) by the lengthening of the C-F(axial) bond, and (c) by the near 90(DEGREES) F-C-O-O dihedral angles.Ph.D.Physical chemistryUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/158462/1/8125130.pd