Chem 455 Spring 2015 Homework 5 due Mon May 4 5:00pm (in box 71 on 3rd floor)

1. Leaky box. An electron with energy eV runs into a potential step of height eV. What is

   the penetration depth of the electron?

2. Tunneling. Consider an electron with 500 meV kinetic energy approaching a 1D potential barrier of

   height 550 meV and width nm. What is the probability that the electron tunnels across the

   barrier?

3. Tunneling. According to the National Electric Code (Table ), the maximum safe current

   through a 12-gauge copper wire ( mm conductor diameter) is 25. A. For higher currents, the

   wire is in danger of overheating and melting the insulation. In an STM (scanning tunneling

   microscope), a current of nA passes from the tip to the...