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We summarize our recent lattice gauge theory computation of the $\Pi_u$ and $\Sigma_u^-$ hybrid static potentials at small quark-antiquark separations. We provide parameterizations of the resulting lattice data points, which can be used for investigating masses and properties of heavy hybrid mesons in the Born-Oppenheimer approximation.

The synthesis of 1,2-naphtho-annelated barrelene derivatives, namely dimethyl-7,12-dihydro-7, 12-ethenobenzo[a]anthracene-13,14-dicarboxylate (4a) and dimethyl-7,14-dihydro-7,14-ethenodibenzo [a,j]-anthracene-15,16-dicarboxylate (4b), and the investigation of their photoreactivity in solution and in the solid state is reported. The irradiation of 4a and 4b resulted in regioselective di-π-methane rearrangements to give semibullvalene products; however, the product distribution is inverted upon changing the reaction medium from solution to the solid state. In solution, an [alpha-naphtho-vinyl bridging predominates as the initial photochemical step because of the selective stabilization of the corresponding transition state, as discussed on the basis of the structures of the related biradical intermediates, whereas the solid-state photoreaction is significantly influenced by the steric constraints within the crystal lattice that only allow a β-naphtho-vinyl bridging. Key words: di-π-methane rearrangement, barrelene derivatives, solid-state photochemistry. On a reahse la synthese de derives condenses 1,2-naphtobarrelenes, a savoir le 7,12-dihydro-7,12-ethenobenzo[a]anthracene-13,14-dicarboxylate de dimethyle (4a) et le 7,14-dihydro-7,14-ethenobenzo[a,j]anthracene-15,16-dicarboxylate de dimethyle (4b), et on a etudie leur photoreactivity en solution et a l'etat solide. L'irradiation des composes 4a et 4b conduit a des rearrangements di-π-methane regioselectifs et a la formation de produits semibullvalenes; toutefois, la distribution des produits est inversee lorsque le milieu reactionnel passe de la solution a 1'etat solide. En solution, un pont α-naphtovinyle predomine comme etape photochimique initiale en raison de la stabilisation selective de l'etat de transition correspondant, tel que discute sur la base des structures des intermediaires biradicalaires apparentes, alors que la photoreaction a l'etat solide est fortement influencee par des contraintes steriques dans le reseau cristallin qui ne permettent que la formation d'un pont β-naphtovinyle. Mots-cles : rearrangement di-π-methane, derives du barrelene, photochimie a l'etat solide. [Traduit par la Redaction], Introduction The di-π-methane rearrangement (1) of benzo-annelated derivatives of barrelene (bicyclo[2.2.2]octatriene) (2) and norbornadiene (bicyclo[2.2.1]heptadiene) (3) has been shown to be an appropriate model reaction for the assessment of the [...]

The formation of solid solution series Cs1-xMxGaQ2-mC64 (M = K, Rb; Q = S, Se; x = 0&-1) was studied by X-ray diffraction and spectroscopic methods, revealing a complete miscibility of CsGaQ2-mC64 with RbGaQ2 and KGaSe2, and a large miscibility gap with KGaS2. All solid solution members exhibit similar Raman spectra, indicating the covalent Ga-Q bonding character. The similar optical band gaps likewise further contribute to this conclusion. Up to a certain degree of substitution, these solid solutions undergo a phase transition similar to CsGaQv2-mC64. The influence of the substitution parameter x on phase transition process was investigated in situ using high-temperature X-ray powder diffraction experiments. Phase-pure solid solutions of the high-temperature polymorphs Cs1-xMxGaQ2-mC16 were obtained up to xmax(K) = 0.1 and xmax(Rb) = 0.3. The crystal structures of these new CsGaQ2-mC16 analogous high-temperature phases were refined from synchrotron diffraction data by Rietveld-refinement. [ABSTRACT FROM AUTHOR]

The synthesis of 1,2-naphtho-annelated barrelene derivatives, namely dimethyl-7,12-dihydro-7,12-ethenobenzo[a]anthracene-13,14-dicarboxylate (4a) and dimethyl-7,14-dihydro-7,14-ethenodibenzo[a,j]-anthracene-15,16-dicarboxylate (4b), and the investigation of their photoreactivity in solution and in the solid state is reported. The irradiation of 4a and 4b resulted in regioselective di-π-methane rearrangements to give semibullvalene products; however, the product distribution is inverted upon changing the reaction medium from solution to the solid state. In solution, an α-naphtho–vinyl bridging predominates as the initial photochemical step because of the selective stabilization of the corresponding transition state, as discussed on the basis of the structures of the related biradical intermediates, whereas the solid-state photoreaction is significantly influenced by the steric constraints within the crystal lattice that only allow a β-naphtho–vinyl bridging. On a réalisé la synthèse de dérivés condensés 1,2-naphtobarrèlènes, à savoir le 7,12-dihydro-7,12-éthénobenzo[a]anthracène-13,14-dicarboxylate de diméthyle (4a) et le 7,14-dihydro-7,14-éthénobenzo[a,j]anthracène-15,16-dicarboxylate de diméthyle (4b), et on a étudié leur photoréactivité en solution et à l’état solide. L’irradiation des composés 4a et 4b conduit à des réarrangements di-π-méthane régiosélectifs et à la formation de produits semibullvalènes; toutefois, la distribution des produits est inversée lorsque le milieu réactionnel passe de la solution à l’état solide. En solution, un pont α-naphtovinyle prédomine comme étape photochimique initiale en raison de la stabilisation sélective de l’état de transition correspondant, tel que discuté sur la base des structures des intermédiaires biradicalaires apparentés, alors que la photoréaction à l’état solide est fortement influencée par des contraintes stériques dans le réseau cristallin qui ne permettent que la formation d’un pont β-naphtovinyle. [ABSTRACT FROM AUTHOR]