rigorous selection rule razan-e gozineš-e farsaxt Fr.: règle de sélection rigoureuse A → selection rule obeyed by → discrete transitions. Among them are: rigorous selection rules for → electric dipole transitions (→ permitted) requiring: 1) ΔJ must be 0 or ± 1 with J = 0 ↔ 0 forbidden. 2) ΔM_{J} = 0, ± 1. 3) → Parity change, i.e. even ↔ odd. |
selection rule razan-e gozineš Fr.: règle de sélection Any of a set of rules specifying the relationships between the → quantum numbers that characterize the initial and final states of a quantum-mechanical system in a → discrete transition. Transitions that do not agree with the selection rules are called → forbidden and have considerably lower probability. There are several types of selection rules (→ rigorous selection rule, → LS coupling, etc.) for → electric dipole transition (→ permitted), → magnetic dipole (forbidden), electric → quadrupole (forbidden), etc. |
site selection gozineš-e sit Fr.: sélection de site The process of choosing a site for an astronomical observatory based on meteorology, seeing conditions, and access to the site. → site; → selection. |