I bought this book "Idiot's Guide to Quantum Physics" I bought it because I know I am an idiot in quantum physics. Now I have a question about the contents. It says that: "The four fundamental forces in nature (gravity, electromagnetism, plus two more that we'll formally introduce in Chapter 16) are just the sort of forces which can be described by potential energy functions. Any apparent "force" that we feel in our everyday lives, is derived from one of these four...." "The four fundamental forces obey the law of conservation of energy we talked about in Chapter 2, and they vary with position. The gravitational force, for example, gets weaker in a predictable way as the separation between two masses is increased. The electromagnetic force gets stronger as a magnet gets closer to a piece of steel. If you've ever stuck a piece of preschool artwork to your refrigerator, you have direct experience with this. These are the qualities that make the potential energy U an excellent stand-in for forces in the Schrodinger equation." My question is.. in spectroscopy or quantum chemistry or solid state physics or any molecular dynamics.. is the potential energy U always related to the four fundamental forces or could it occur from other molecular dynamics.. and what kinds of molecular dynamics that doesn't involve the four fundamental forces? My last question.. in quantum chemistry and spectroscopy.. is it all about getting the "potential" terms to solve for the Schrodinger equations. For complex molecular dynamics.. how do you determine the potential of all the combined stuff? Thanks.