Metastable Quenching Spectroscopy MQS

State or vibrational energies. If the current across the metal-insulator-metal sandwich is recorded as a function of applied voltage, the current increases as the threshold for each state or vibrational mode is crossed. The increases in current are in fact very small, and for improved detectability the current is double-differentiated with respect to voltage, thereby providing, in effect, a vibrational spectrum that can be compared directly with free-molecule IR and Raman spectra. 

to optimize the energy resolution by reducing the contribution of thermal broadening to the line-width, and lead is, of course, superconducting at that temperature. 

Normally not one, but several, junctions are fabricated simultaneously, because the likelihood of junction failure always exists. After fabrication the electrical connections are made to the metal electrodes, the junctions are dropped into liquid helium, and measurements are commenced immediately. 

Although insulators other than aluminum oxide have been tried, aluminum is still used almost universally because it is easy to evaporate and forms a limiting oxide layer of high uniformity. To be restricted, therefore, to adsorption of molecules on aluminum oxide might seem like a disadvantage of the technique, but aluminum oxide is very important in many technical fields. Many catalysts are supported on alumina in various forms, as are sensors, and in addition the properties of the oxide film on aluminum metal are of the greatest interest in adhesion and protection. 

Surface and Thin Film Analysis Principles, Instrumentation, Applications 

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Penning ioni2ation electron spectroscopy is also called (i) metastable atom electron spectroscopy (MAES), (ii) metastable deexdtation spectroscopy (MDS), (iii) metastable quenching spectroscopy (MQS), and (iv) metastable impact electron spectroscopy (MIES), where atom at metastable state is used instead of photon to ionize the target material When a slow, long-lived, electronically excited metastable atom hits a solid surface, most of its excitation energy is used to eject electrons from the surface. Unlike photons used for UPS, metastable atoms do not penetrate into the bulk of the solid. PIES, therefore, excites the outermost surface layer selectively (39). 

Metastable De-excitation Spectroscopy (MDS), also known as Penning Ionization Electron Spectroscopy (PIES) and Metastable Quenching Spectroscopy (MQS)... 

INS Ion neutralization spectroscopy MQS Metastable quenching spectroscopy SSIMS Static secondary-ion mass spectrometry ISS Ion scattering spectroscopy... 

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