Principles of Quantum Mechanics

Chapter 12

The Spin

12.1  INTRODUCTION

In Chapter 10, we solved Schrodinger equation for an electron in hydrogen atom and found discrete values of energy and orbital angular momentum. When an electron makes transition from higher energy state with energy E_m to a lower energy state with energy E_n, allowed by selection rules (to be discussed in a later chapter), the emitted radiation has wavelength λ = hc /(E_m − E_n). When the predicted spectrum was compared with the observed spectral lines, there was agreement in almost whole spectrum except in finer details of (some) lines. In fact, the theoretical spectrum cannot account for a few additional spectral lines seen experimentally. Most important of these is the fact that many of the observed spectral ...