Spin- and angle-resolved photoemission on topological materials

A historical review of spin- and angle-resolved photoemission on topological materials is presented, aimed at readers who are new to the field or who wish to obtain an overview of the activities in the field. The main focus lies on topological insulators, but also Weyl and other semimetals will be discussed. Further it will be explained why the measured spin polarisation from a spin polarised state should always add up to 100% and how spin interference effects influence the measured spin texture.Comment: Invited review article for special issue "ARPES Studies of Topological Materials" in Electronic Structur

Peripheral Metal Complexes: Chlorophyll “Isomers” with Magnesium Bound to the Ring E ß-Keto Ester System

Peripheral magnesium complexes of methyl pheophorbides a and b, bacteriomethyl pheophorbide a, bacteriopheophytin a, and protopheophytin a have been prepared and characterized by UV-vis, IR, ‘H NMR, and luminescence spectroscopy. In these compounds, Mg is bound to the peripheral p-keto ester system present in most chlorophylls rather than to the central tetrapyrrole cavity as in the chlorophyll proper. The ligand exchange reactions at Mg have been characterized, and the equilibrium between the peripheral complexes and their free ligands has been studied over the concentration range lo-’- M. AGO for complex formation has been determined by ’H NMR spectroscopy

Business Cycle at a Sectoral Level: the Portuguese Case

The existence of comovement across different sectors is an important feature of the business cycle definition. The purpose of this work is to characterise the Portuguese sectoral business cycle, with particular emphasis on the comovement phenomenon, for the years 1953-2003 in terms of both GVA and employment. Inthe last fifty years substantial structural changes were observed in the Portuguese economy. These changes mean that some sectors, notably the service sectors, are growing in relative terms. Despite the existing differences in characteristics, such as trend and volatility, there is evidence for the presence of comovement among Portuguese activity sectors. A discussion on the causes of such phenomenon, such as the input-output linkages, in light of the Portuguese economy is done.