ECE G201 H.W. #1, Due January 16, 2009

1. Problem 1.3, Text.

2. a) Develop a model for the allowed energy levels of the He+ ion using classical mechanics and the Bohr postulate that the electron's angular momentum is quantized. Recall that the helium atom consists of two neutrons, two protons, and two electrons. The helium ion will have been stripped of one of these electrons. So the nucleus has a charge of +2q and the remaining electron will have a charge of q (where q=1.609x10-19 Coulombs).

b) Numerically compute the allowed energy states for quantum numbers from n=1 to n=6.

c) Using the "Golden Rule" that the wavelength of photon is lambda = 1.24/E(eV), find the spectrum of light emitted by a helium ion as its electron transitions between allowed levels.

d) Find a reference source for the "line spectra of the elements" and confirm that your calculations for the allowed energy levels are correct by showing that the experimental wavelengths of photons emitted by He+ agree with your calculations. (the CRC Handbook of Chemistry and Physics is one source. Please note that spectroscopists label neutral helium as "He I" and the singly-charged helium ion as "He II"). For the observed wavelengths of light emitted by He+, determine the initial and final quantum numbers that are responsible for each wavelength. For example, if E2-E1 = 40.9 eV, the transition will yield a photon with lambda = 0.0303 microns or 303 Angstroms. Some small numerical errors should be expected.

3. Problem 1.2, Text.

4. Problem 1.5, Text.

5. Problem 1.6, Text.

6. Tell me:

a. What is your background in semiconductor devices.

b. What is your area of study or particular interest in semiconductor devices.