Surface barrier sensitivity of positronium formation at surfaces

Smooth surface barriers are introduced to calculate wave functions for positrons and electrons at metal surfaces. The calculated positronium formation probability is very sensitive to the shape of the surface barrier potential. According to our calculations, the calculated positronium energy spectrum is sensitive not only to the positronic surface barrier but also to the electronic surface barrier potential. Thus, positronium formation may be one of the most powerful spectroscopies to measure the electronic surface barrier potential shape.