Energetic consideration applied to the mass spectra of some aromatic compounds

It is shown that the ‘metastable’ mass spectra of a series of monosubstituted benzenes are consistent with reaction over the lowest available energy surfaces. The non-occurrence of some qualitatively possible decomposition pathways may therefore be used to place lower limits on the heats of formation of gaseous cations. Conversely, where characterized reactions are preempted by new reactions upon introduction of additional substituents, upper limits may be placed upon the heats of formation of the ionic products of the new reactions. The concepts are employed to deduce that C₃H₆ elimination from n-butylbenzence subsequent to ionization leads to ionized toluene rather than ionized methyleneclohexadience.     

Energy transfer in rare earth-doped CaWO4 after red edge excitation

Host sensitized energy transfer in CaWO₄ doped with Eu³⁺ and Sm³⁺ is investigated using pulsed laser time-resolved spectroscopy techniques. The excitation is into the long wavelength tail of the absorption edge and the results indicate that this selectively excites tungstate ions which are located next to activator impurity ions. The subsequent energy transfer is found to be consistent with a single step, nearest neighbor process. Both electric dipole-dipole and exchange interactions can predict strong enough transfer to account for the observed rates. These results are compared to those obtained previously for broad band excitation into the highest energy absorption bands of CaWO₄ crystals.     

Time-dependent entropies associated with single mode radiation in a cavity

The time-dependent information theory entropy and generalized Gibbs entropy are evaluated for a continuous time Markov process (single mode radiation in a cavity).     

The connection between the thermodynamics of chemisorption on semiconductor surfaces and surface scattering of carriers

An explicit theoretical relation is derived which connects the thermodynamics of chemisorption on semiconductor surfaces with the scattering rate of conduction and valence band carriers by charges localized in the chemisorption bonds.     

Commutators and scattering theory

We use commutators to find classes of operators which are smooth with respect to the HamiltonianH for a system of quantum mechanical particles which repel each other. It follows thatH is absolutely continuous, the wave operators are complete in many cases when they exist and limits of momentum observables as time approaches ± exist even in cases where the long range of the interaction precludes existence of the wave operators.