The Barrier Scattering model computes the 1D quantum scattering-state wave function and shows its time evolution for an arbitrary potential V(x) on the interval [xmin,xmax]. It is a supplemental simulation for the article "Smooth double barriers in quantum mechanics" by Avik Dutt and Sayan Kar in the American Journal of Physics 78(12), 1352-1360 (2010) and has been approved by the authors and the American Journal of Physics (AJP) editor.

The transmission probability as a function of incident particle energy is shown in a second window.  Users can select a predefined V(x) or their own function and can vary the energy E and then observe the wave function and its time evolution.  The transmission amplitude is computed and a data point is added to the transmission probability graph when the energy is changed.  Because resonances are often sharp, the transmission probability graph has an energy-scan option that automatically computes the transmission coefficient as the energy is incremented.  Set the energy below the resonance and choose a small energy increment ?E to obtain a high-resolution transmission probability spectrum.

The Barrier Scattering model was created using the Easy Java Simulations (EJS) modeling tool.  It is distributed as a ready-to-run (compiled) Java archive.  Double clicking the ejs_qm_BarrierScattering.jar file will run the program if Java is installed.

Please note that this resource requires at least version 1.5 of Java (JRE).