Serendipitous Meanderings and Adventures With Molecular Beams

Abstract

s Abstract This is the story of a native-born American who came as a postdoc to the country of his parents, Germany. There, by good fortune, he could participate in the revival and the rebuilding of the physical sciences following the ravishments of the Second World War, becoming at the age of 38, the director of a Max-Planck-Institut in Göttingen. Working under nearly ideal conditions, he carried out basic research using molecular beams. Aided by many active, youthfully impulsive, yet perceptive and imaginative, students and experienced knowledgeable guest scientists from many countries, he enjoyed exciting adventures into unknown landscapes in the fields of molecular gas-phase interactions and solid-surface phenomena and, most recently, in the realms of quantum liquids and solids.

Dynamics of third order direct three-body recombination of heavy ions

“…Toennies' original articles and reviews on dynamics of atomic and molecular collisions have served and still serve as the main manuals for the authors of this paper and many other scientists working in this field of fundamental science. 1,2 Reactions of recombination of atoms, small radicals, and ions play a major role in representations of the mechanisms of complex chemical processes as one of the main routes of death of active particles. Direct three-body recombination of alkali ions M + and halide ions X À proceeds according to the scheme…”

“…By now, as far as the authors know, the dynamics of three-body recombination of ions has been explored this way only for recombination of the ions Cs + and Br À in the presence of rare gas and mercury atoms. [3][4][5][6][7][8][9][10][11][12][13] In this paper, we consider direct three-body recombination of the ions Cs + + F À and Cs + + I À according to the general scheme (1) in the collision energy range 1-10 eV typical for low temperature plasma:…”

“…The main purpose of the paper is to describe the dynamical features of the processes (2) which differ in the masses of the halide ion and of the rare gas atom and in the corresponding interaction potentials Cs + -X À , Cs + -R, and X À -R. These differences should affect the overall dynamics of the reactions as well as the dynamics of all the main stages of the processes. It is interesting to note that in the systems M + -X À -R in question, besides the termolecular recombination reaction (1), one more recombination process can occur, namely, RM + + X À -MX + R.…”

“…This is a two order bimolecular reaction (the final step of one of the indirect recombination mechanisms known as the bound complex mechanism 14,15 ), and its dynamics is therefore drastically different from that of the reactions (1). By now, to the best of the authors' knowledge, the dynamics of the process (3) has been examined only for XeCs + + Br À .…”

Design of a modular and versatile interlock system for ultrahigh vacuum machines: A crossed molecular beam setup as a case study

“…[1][2][3][4][5][6][7][8][9][10][11][12] In contrast to bulk experiments, where the reactants are mixed, the main advantage of the crossed beam approach is the capability to form the reactants in separate, supersonic beams. In principle, both reactant beams can be prepared in welldefined quantum states before they cross at a specific collision energy under the single collision conditions.…”