The molecular beam method basic concepts and examples of bimolecular reaction studies

The Molecular Beam Method Basic Concepts and Examples of Bimolecular Reaction Studies 

A molecular beam is a collimated ensemble of molecules travelling in a collisionless regime through an evacuated chamber. The beam can be directed towards another beam, a gas cell or a surface. In general, the scattering produced from these interactions provides information about intermolecular forces, energy transfer or the dynamics of a chemical reaction either in the gas phase or gas-surface interaction. 

Of particular interest is the so-called crossed-beam method to study the dynamics of elementary reactions a field, in which D.R. Herschbach and Y.T. Lee were awarded the 1986 Nobel Prize in Chemistry for their fundamental development work. A key feature of the crossed-beam technique is to work under single collision conditions (see below). J.C. Polanyi shared the 1986 Nobel Prize in chemistry for his contribution in the study of the dynamics of elementary reactions using other methods, such as chemiluminescence and dynamical calculations. 

The process leading to the generation of effusive beams is relatively simple. An oven contains the 

The spatial (angular) distribution of the beam intensity 1(0) departing from the oven orifice follows that of a Maxwell-Boltzmann distribution of molecules striking on the orifice area, i.e. it follows a cosine distribution given by 

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CH21 THE MOLECULAR BEAM METHOD BASIC CONCEPTS AND EXAMPLES OF BIMOLECULAR REACTION STUDIES... 

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