|Oct14-04, 04:49 PM||#1| Rotational energy levels Are rotational
energy levels of a molecule in general equally spaced or does
the spacing increase with energy? How about a diatomic molecule;
I have seen a derivation showing that the rotational levels in a
diatomic molecule are equally spaced, but when drawn in an
energy level diagram they clearly aren't? What is right? And
another thing; in my book the expression for the rotational and
vibrational energies of a diatomic molecule is derived in terms
of a classical "dumb-bell"-picture? How is this justified taking
quantum mechanics into account? |Oct14-04, 05:58 PM||#2| No,
even in the most simple diatomic molecule rotational levels are
not equally spaced. If you look at any rotational spectrum of
such molecules you will clearly appreciate it. You will see how
the first lines are separated more or less a 2B distance (B is
the rotational constant) but they get closer when increasing
frequency. But be carefull with this, the energy levels get more
separated when