001B30C40 Multiple resonances (including double and higher-order resonance processes, such as double nuclear magnetic resonance, electron double resonance and microwave optical double resonance).
001B30D10 General theories and models of atomic and molecular collisions and interactions (including statistical theories, transition state, stochastic and trajectory models, etc.).
001E03A90 Historical astronomy and archaeoastronomy; and other topics in fundamental astronomy and astrophysics; instrumentation, techniques, and astronomical observations.