Laser-Stimulated Desorption of Hydrogen in Palladium for Dynamic Hydrogen Sorption Microanalysis.

Hydrogen is a volatile element, both as a molecular gas and as atomic hydrogen in materials. A method is described for the detection of the corresponding dynamic hydrogen in matter, as opposed to the relatively stable bond hydrogen ("static hydrogen"). The method is based on laser-stimulated hydrogen desorption using nanosecond laser pulses in the UV optical range. The principle, already established for surface hydrogen on nonabsorbent metals has been extended to hydrogen affine bulk systems. The feasibility of the idea is demonstrated by quantifying hydrogen in hydrogen-permeable metal membranes. Model experiments, such as HD exchange, provide input to the model to extract the surface hydrogen concentration of dynamic hydrogen from laser-stimulated hydrogen desorption while eliminating the influence of the laser-matter interaction on the quantification. An estimate of the limit of detection is given.