We report a two-parameter formula (the Gemini formula) that predicts the strongest emission wavelength of d-block elements with one outer s-electron to 2. 0% mean error across 11 elements. The formula introduces a new np-orbital screening parameter (fₚ = 0. 910) motivated by the angular momentum dependence of orbital penetration and confirmed by two independent empirical boundary conditions. The central empirical finding is that silver's strongest emission line is one octave above hydrogen's Balmer-alpha to within 0. 02%.
Joseph Vanvactor (Tue,) studied this question.