Theorem relating spatial and temporal harmonics for nuclear interlevel transfer driven by collective electronic oscillation

A crucial step in the development of gamma-ray lasers will be the discovery of an efficient mechanism for nuclear interlevel transfer. One promising mechanism uses the near-field interaction between the nucleus and laser-driven collective electronic oscillations. This paper proves an important theorem relating spatial and temporal harmonics which states that 2(2n)-poles are driven only at even multiples of the laser frequency, while 2(2n+1)-poles are driven only at odd multiples of the laser frequency. The theorem's relevance to a proposed interlevel-transfer experiment is discussed.