Narrow atomic transitions with enhanced sensitivity to variation of the fine structure constant

To study the possible variation of the fine structure constant, α, in laboratory experiments, we propose using narrow lines that correspond to atomic transitions between close lying, long-lived atomic states of different configurations. The small transition frequency, coupled with differences in the electron structure ensures a strong enhancement of the relative frequency change compared to a possible change in α. The small linewidth makes it possible to perform very accurate measurements. These two features, when combined, make the measurements very sensitive to any variation of α.