Comparing particle emission scenarios in hydrodynamics: Continuous emission vs. freeze-out

The usual particle emission scenario used in hydrodynamics presupposes that particles instantaneously stop interacting (freeze-out) once they reach some three dimensional surface. Another formalism has been developed recently where particle emission occurs continuously during the whole expansion of thermalized matter. Here we compare both mechanisms in a simplified hydrodynamical framework and show that they lead to a drastically different interpretation of data.     

Multiparticle unitarity and diffractive amplitudes

Generalizing the results of previous work, an explicit construction of elastic and inelastic diffractive amplitudes through multiparticle unitarity is given starting from a simple parametrization of non-diffractive production amplitudes. The energy dependent interference mechanism which has been previously shown to be essential to produce the diffraction peak in the elastic process is now seen to be also responsible, in a natural way, for the leading particle effect which dominates production yields.     

Coherent potential approximation to order-disorder transition in binary alloys

A band theory of order-disorder transition in an AB alloy is studied using the locator formalism in the coherent potential approximation. The influence of the difference in the band widths of A and B metals on the transition temperature is discussed.     

Anomalously high metallization pressure of solid neon

The equation of state of solid fcc neon at T = 0 K is calculated by the local density functional theory in the muffin-tin approximation. The calculated equation of state is in good agreement with Hawke et al.'s experimental value at about 6 Mbar by magnetic flux compression and also agrees remarkably well with that by the quantum statistical model in the region of extremely high pressures. If no structural phase transition occurs up to metallization, solid neon becomes metallic at a molar volume of 0.256 cm³/mole or at a pressure of 1.58 × 10³ Mbar. This is the highest metallization pressure ever reported.     

Alpha-arylation of esters catalyzed by the Pd(I) dimer {[P(t-Bu)3]PdBr}2

Conditions for the coupling of bromoarenes with esters using a single base and catalyst with improved turnover numbers are described. These general conditions were made possible by using the Pd(I) catalyst {[P(t-Bu)3]PdBr}2. Reactions of acetates, propionates, and isobutyrates are presented, and reactions of all three classes of esters on a 10 g scale are described.     

Palladium-catalyzed alpha-arylation of esters with chloroarenes

Palladium-catalyzed alpha-arylations of esters with chloroarenes are reported. The reactions of chloroarenes with the sodium enolates of tert-butyl propionate and methyl isobutyrate occur in high yields with 0.2-1 mol % of {[P(t-Bu)3]PdBr}2 or the combination of Pd(dba)2 and P(t-Bu)3 as catalyst. The reactions of chloroarenes with the Reformatsky reagent of tert-butyl acetate were most challenging but occurred in high yields for chlorobenzene and electron-poor chloroarenes catalyzed by 1 mol % of Pd(dba)2 and pentaphenylferrocenyl di-tert-butylphosphine (Q-phos).