P 12.13 use the virial theorem to obtain an expression fot the relation between the mean kinetic and potential energies of an electron in a hydrogen atom. P 13.2 A series of lines in the spectrum of atomic hydrogen lie at 656.46 nm, 434.17 nm, and 410.29 nm. This is the Balmer series in the visible spectrum, so the lowest energy level possible is 2. IR selection rule- motion corresponding to a normal mode should be accompanied by a change in dipole moment.
All modes are both infrared and Raman active because the selection rules apply to all.
The symmetric stretch correspond to Raman and not to infrared. Calculate the contour length and the root mean square separation for polyethylene with a molar mass of 280 kg mol-1. So the randomly coiled chain is much shorter than the stretched chain.