Page 316 - Radiochemistry and nuclear chemistry

CHAPTER 11

Nuclear Structure

Contents

11.1. Requirements of a nuclear model 300
11.1.1. Some general nuclear properties 300
11.1.2. Quantized energy levels 301
11.1.3. The nuclear potential well 302
11.2. Rotational energy and angular momentum 303
11.2.1. Rotational (mechanical) energy 303
11.2.2. Angular momentum 304
11.2.3. Coupling of spin and orbital angular moments 305
11.2.4. Magnetic moments 307
11.2.5. Precession 309
11.3. The single-particle shell model 311
11.3.1. Quantum number rules 311
11.3.2. Nuclei without nucleon spin-orbit coupling 312
11.3.3. Nuclear level scheme with nucleon spin-orbit coupling 312
11.3.4. The nuclear spin 314
11.4. Deformed nuclei 316
11.4.1. Deformation index 316
11.4.2. Electric multipoles 316
11.4.3. The collective nuclear model 317
11.5. The unified model of deformed nuclei 318
11.6. Interaction between the nuclear spin and the electron structure 320
11.6.1. Hyperfine spectra 320
11.6.2. Atomic beams 322
11.6.3. Nuclear magnetic resonance 323
11.7. Radioactive decay and nuclear structure 324
11.7.1. Gamma-decay 324
11.7.2. Beta-decay 326
11.7.3. Alpha-decay theory 326
11.7.4. Spontaneous fission 330
11.8. Exercises 333
11.9. Literature 333

Throughout the ages and in every civilization, people have developed explanations of
observed behaviors. These explanations are based on the principle of causality, i.e. every
effect has a cause and the same cause produces always the same effect. We call these
explanations models.
Scientists are professional model-builders. Observed phenomena are used to develop a
model, which then is tested through new experiments. This is familiar to every chemist:
although we cannot see the atoms and molecules which we add into a reaction vessel, we

299