Hi everybody, This is my first post in this forum although I started following it some time ago. My question is related to rotational properties involving harmonic oscillator model. 1. The problem statement, all variables and given/known data We are told to evaluate the expectation value of the rotational constant of a diatomic molecule for each vibrational state considering the Harmonic Oscillator model. I have started with the ground vibrational state, but the entire solution of the problem should include an expression for the dependance of the expectation value of B on the quantum number [itex]\upsilon[/itex] and other parameters. 2. Relevant equations http://img36.imageshack.us/img36/3463/physicsforum1.jpg [Broken] 3. The attempt at a solution http://img189.imageshack.us/img189/1899/physicsforum2.jpg [Broken] Do you agree with the way I am solving the problem? I don´t find the last gaussian-like definite integral in any of the tables I have consulted and I cannot find the solution by myself. Could you make me a suggestion about it? Thanks in advance.