A New Option for a Search for Alpha Variation: Narrow Transitions with   Enhanced Sensitivity
  We consider several transitions between narrow lines that have an enhanced sensitivity to a possible variation of the fine structure constant, alpha. This enhancement may allow a search to be performed with an effective suppression of the systematic sources of uncertainty that are unavoidable in conventional high-resolution spectroscopic measurements. In the future this may provide the strongest laboratory constraints on alpha variation. 
S. G. Karshenboim, A. Yu. Nevsky, E. J. Angstmann, V. A. Dzuba, and V.   V. Flambaum