13C?13C spin coupling constants in tetrahydronaphthylene,hexahydrobenzanthracene and benzo[a]pyrene derivatives

The ¹³C? ¹³C spin coupling constants have been determined in substituted [1-¹³C]tetrahydronaphthylenes, [5-¹³C]hexahydrobenzanthracenes and [5-¹³C]benzanthracene. In addition, the ¹³C? ¹³C spin coupling constants for 7-hydroxy[7-¹³C]benzopyrene, trans-7,8-dihydro[7-¹³C]benzopyrene-7,8-diol and trans-7,8-dihydro[10-¹³C]benzopyrene-7,8-diol are reported, together with the one-bond carbon-carbon coupling constants between C-4 and C-5 in selected 4,5-disubstituted benzopyrenes. Values for the directly bonded coupling constants and long-range coupling constants are similar to those reported previously for other aromatic and aliphatic systems. Substituent effects on carbon-carbon coupling are compared for similarly substituted cyclic and acyclic systems.     

Martingales,the smoothing index and ergodic theory

A classical theorem of Meyer Jerison which shows that the convergence in the pointwise ergodic theorem is equivalent to the convergence of an associated martingale is expanded to a conditional setting. An equiconvergence theorem of the type established for martingales by N.F.G. Martin and E. Boylan is established in the ergodic case for an ergodic, non-invertible, measure-preserving transformation.     

Multipole interactions and macroscopic differences in ortho and para hydrogen

Differences in the low temperature viscosity and virial coefficients of ortho and para hydrogen are attributed to centrifugal stretching, exchange symmetry, and, to a lesser extent, molecular anisotorpy. Of the latter, quadrupole interactions are the most important.     

Some phosphine oxide complexes of thorium and uranium tetrabromides

Trimethyl phosphine oxide (tmpo) complexes, MBr₄(tmpo)₆ (M = Th and U) have been prepared by reactions in non-aqueous solvents. Some chemical properties, i. r., and the u. v. visible spectra of uranium complex are reported.     

Band structure features involved in charge transfer in bonds

In contrast with previous theories, we show that the wave function near the gap between the lowest two valence bands in zinc-blend compounds is essential to describe the charge transfer characteristic of the ionic bond.