Possibility of establishment of a quantum frequency standard for the visible range using an intercombination spectral transition in the ytterbium atom

A comparative analysis is made of the characteristics of the 6¹S₀– 6³P₁ intercombination transition in the ytterbium atom with the characteristics of the corresponding n¹S₀–n³P₁ transitions in alkaline earth atoms: magnesium, calcium, and strontium. It is suggested that the transition in the ytterbium atom can be used as a reference point for a quantum frequency standard in the visible range.