No description available.

Complexes of aromatic hydrocarbons (donors) with electron acceptors such as 1,3,5-trinitrobenzene (TNB) are stabilized principally by resonance between a dative and a "no-bond" wave function: ϕN = a ψ օ (DA) + b ψ ₁ (D⁺A⁻) By means of second-order perturbation theory it can be shown that, providing certain symmetry requirements are met, the energy WN corresponding to ϕN will be less than that of the free separated donor and acceptor. The resulting molecular complexes have a stability of 2-10 kcal, and usually possess a colour which is associated with a transition between the ground state WN and an excited state WE. These charge-transfer spectra have previously been studied only in solution, and have been useful sources of thermodynamic data. In order to learn more of the transition itself, it is necessary to study the spectrum of the crystal, where the molecules are held in fixed and (sometimes) known positions. The procedure by which the polarized crystal spectrum of the anthracene-TNB complex was obtained is briefly described. Comparison of the observed spectrum with the partially-known crystal structure has shown 1) The supposition that the transition dipole moment is perpendicular to the planes of the aromatic rings is supported; 2) Vibrational structure can exist in a charge-transfer band; this is the first reported observation of it; 3) The band is split into two oppositely-polarized components, differing in energy by about 200/cm. An attempt is made to explain this splitting in terms of Davydov's "weak-coupling" model of a crystal, in which degenerate molecular states are presumed to become crystal states whose degeneracy depends on the symmetry of the associated unit-cell wave functions. Some preliminary steps are described which should eventually lead to the detailed calculation of this effect in the present case. / Science, Faculty of / Chemistry, Department of / Graduate

The solubility of anthracene was measured in binary and ternary co-solvent-water systems. The binary systems consisted of water and a completely miscible organic solvent (CMOS); while the ternary system incorporated a partially miscible organic solvent (PMOS) into the binary systems. The data were used to test the following model:(UNFORMATTED TABLE OR EQUATION FOLLOWS) log Sᵃ(c,p,w) = log Sᵃ(w) + f(c) σᵃ(c) + [(Sᴾ(w) 10 (f(c) σᴾ(c))/D(p)] σᵃ(p). (TABLE/EQUATION ENDS) The terms on the right of the equality sign are the aqueous solubility of anthracene, the solubility of anthracene in CMOS-water, and the solubility of anthracene due to the incorporation of the PMOS, respectively. This model predicts that the incorporation of a PMOS, as a solubilized solute, in CMOS-water mixtures can lead to an increase in the solubility of anthracene due to the cosolvency effect of the PMOS. The results indicate a good correlation between the observed vs. predicted increase in solubility. The deviations observed may be explained by the interactions between the solvent components.

No description available.

Thesis (M.A.)--Boston University / It hae been proposed in the literature (18) that complexes between aromatic nitro compounds and aromatic bfdrocarbons are the reeult of an electron transfer from the hydrocarbon to the nitro compound with the resultant formation of ions. The conductivity of such a complex, that between anthracene and trinitrobenzene, was measured in liquid sulfur dioxide to teat this hypothesis. The conductivity of the complex was found to be the sum of the two components, which indicated no ions present in solution and pointed to the non-existence of the complex in solution. Spectral work done by R. W. Weston (20) supports the contention that the complex does not exist in solution. Ultraviolet absorption spectrum of the complex in liquid sulfur dioxide was the sum of the spectra of the two components. The conductivity of triphenylcarbinol was measured in liquid sulfur dioxide in a concentration range of 200-195,000 liters per mole. With magnesium perchlorate as the drying agent in the gas train a drift at the initial concentration, as well as lower conductivities at the higher concentrations was noted, in contrast to the work of Glazer (3). With OaOl2 as the drying agent, no drift was observed, and conductivity values were in general agreement with those of Glazer. A possible mechanism for the observed results has been suggested.

Thesis--M. Phil., University of Hong Kong, 1981.

published_or_final_version / Physics / Master / Master of Philosophy

Thesis (Ph. D.)--University of Wisconsin--Madison, 1951. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 150-154).

Thesis (PH. D.)--Cornell university. / "Reprinted from the Journal of physical chemistry, vol. 15, p. 845 (1911)" "References": p. 864-865.

When a crystal of anthracene with a small added "impurity" of naphthacene is excited by X-radiation or ultraviolet light the fluorescent spectrum includes or consists almost totally of naphthacene bands. The energy absorbed by the anthracene is said to have been transferred to the naphthacene. The same result is obtained with certain other "impurities" and matrix compounds. Although this process had been known to exist for some time, no detailed quantitative experiments had been performed. The author used an arrangement including a Beckman Model DU Quartz Spectrophotometer used as a mono-chrometer and a 931-A photomultiplier tube as a detector to obtain fluorescent spectra. This arrangement combined very great sensitivity with great convenience of operation. The spectra of crystals of anthracene with naphthacene, naphthalene with naphthacene, and naphthalene with 1,2,5,6-dibenzanthracene were obtained. The maximum intensity of fluorescence of the impurity bands occurred at 2.93 x 10ˉ⁴ moles naphthacene per mole anthracene in the crystals of anthracene plus naphthacene: at 3.38 x 10ˉ⁵ moles naphthacene per mole naphthalene in the crystals of naphthalene plus naphthacene: and at 1.01 x 10ˉ⁴ moles 1,2,5,6-dibenzanthracene per mole naphthalene in the crystals of naphthalene plus 1,2,5,6-dibenzanthracene. The fluorescent spectrum of a crystal of anthracene was obtained using first X-ray excitation and then ultra-violet excitation. The two sources of excitation gave rise to different spectra. A theory of the mechanism of energy transfer and a hypothetical set of energy levels for the crystals with added impurities are given. The method used to grow some of the crystals used in this research is given in an Appendix. / Science, Faculty of / Physics and Astronomy, Department of / Graduate