PCHEM 3060 Exam Solutions: Quantum Mechanics Concepts, Exams of Physical Chemistry

Download PCHEM 3060 Exam Solutions: Quantum Mechanics Concepts and more Exams Physical Chemistry in PDF only on Docsity! Exam solution for PCHEM 3060 17th October 2005 17th October 2005 (1.) For what reason(s)are the energies of the quantum mechanical systems quantized? Here i wanted to hear: Boundary conditions!!! But still if you wrote sth. about quantized Energy levels and it was correct, i still gave you 2Pts for that! (2.) Describe Heisenberg’s Uncertainty principle. Well, you can’t measure the position and momentum of a particle simultanously with absolute precision. (3.) Which motion does a harmonic oscillator describe in molecules. Vibrational motions (4.) What is degeneracy? Give an example. Degeneracy is if you can describe different states possess the same energy value..for instance the p-orbitals. (5.) List three facts about quantum mechanics that are in contradiction with the cor- responding classical mechanics. Here, you could have mentioned Black body radiation, Heat capacity, Photoelec- tric effect as well as Heisenbergs uncertainty principle.... (5.) Since p̂x and p̂y coummute, every eigenfunction of p̂x is also an eigenfunction of p̂y. True False (6.) Eigenfunctions of the same operator that have different eigenvalues are always orthogonal. True False (7.) [L̂2, L̂x],[L̂2, L̂y],[L̂2, L̂z] all commute and thereforeL̂2, L̂x.L̂yandL̂z can be mesured simultaneously with absolute certainty. True False (8.) The threshold wavelength for potassium metal is 564 nm. What is its work func- tion? What is the kinetic energy of electrons ejected if radiation of wavelength 410 nm is used? 2