Photon‐stimulated Desorption and X‐ray Standing Waves

Photon-stimulated desorption and x-ray standing waves

Introduction X-ray standing waves (XSW) using electrons and fluorescence photons as secondary signals has become a standard technique to determine adsorbate structures. However, when a sample is irradiated by intense light, desorption of ions is also a frequently observed phenomenon which is known as photon-stimulated desorption (PSD). But, this signal is of a fundamentally different physical n...

Standing Waves: the Equilateral Triangle

It is well known that symmetry considerations can often be a powerful tool for simplifying physical systems. We consider a wave which satisfies the Helmholtz equation in a region with some given symmetry, and note that any solution can be transformed by that symmetry to give another solution. Using this simple observation we describe a number of necessary conditions for wave solutions. For boun...

Bifurcation behavior of standing waves

Two different types of standing waves (SW0 and SWπ) can appear instead of spiral vortices from a supercritical Hopf bifurcation in counter-rotating Taylor-Couette flow for sufficiently small aspect ratios [1,2]. The bifurcation sequence from basic flow to spiral vortices via SW0 can include modulated waves, homoclinic bifurcations, and hysteresis as a consequence of broken translational invaria...

Large scale instability of nonlinear standing waves

Lateral resolution enhancement with standing evanescent waves.

A high-resolution fluorescence microscopy technique has been developed that achieves a lateral resolution of better than one sixth of the emission wavelength (FWHM). By use of a total-internal-reflection geometry, standing evanescent waves are generated that spatially modulate the excitation of the sample. An enhanced two-dimensional image is formed from a weighted sum of images taken at differ...