Experimental branching fractions, transition probabilities, and oscillator strengths of La i

Experimental branching fractions of 65 lines in La i were measured based on grating spectroscopy of a lanthanum hollow cathode lamp. Combining these branching fractions with previous energy lifetimes measured using time-resolved laser-induced fluorescence (TR-LIF) spectroscopy, absolute transition probabilities, and oscillator strengths were determined for 34 lines belonging to transitions 4f5d6s-5d6s(2), 4f5d6s-5d(3), 5d(2)6p-5d6s(2), 5d(2)7p-5d(2)6s, and for 31 lines associated with uncertain configurations due to dramatic configuration interaction mixings. These fundamental atomic data will help make atomic models more realistic and provide useful parameters for future astrophysical spectral analysis.