| 释义 |
f-sum rule f-sum rule[′ef ‚səm ‚rül] (atomic physics) The rule that the sum of the f values (or oscillator strengths) of absorption transitions of an atom in a given state, minus the sum of the f values of the emission transitions in that state, equals the number of electrons which take part in these transitions. Also known as Thomas-Reiche-Kuhn sum rule. |