For one electron to jump to a higher energy level, fine. Its not that hard.
But if you put into account the billions of atoms that would make up even a small part of Raiser, and for them all to simultaneously jump at once and retain that excited energy state, the chances of it happening are extremely slim.
As if that wasn't enough, theres also the problem with the structure of the Gundam when it falls back from the excited state. It would be rather &^*#&^*-ing hard to get the protons to stay in the similar general shape, wouldn't it.
So, with the current level of technology, quantization is but a 00R fan's dream.