Timothy Coons 18 Mar 2009 15:07
hey Yamalia….nice work!….So the number of distinct or indepenent lattice waves, with different wave functions in a crystal is not infinite but depends on the number of atoms N. My understanding is that each mode or state of lattice vibration is an independent lattice vibration and the energy can be increased or decreased by only the quantum amount of 'hw'. And since the mode values inside and outside the range of -(3.14)/a and (3.14)/a are the same then the maximum number of modes is N. And for a 3-D crystal the number of modes is 3N. So I dont know if you want to get a little more into finding vibration modes, but overall nice job.