Absolute transition probabilities in Ta i and W i

Branching ratios are reported for 253 spectral lines in Ta i and 309 lines in W i. New radiative lifetime measurements of 39 W i levels are also reported. The branching ratios are combined with the newly measured W i and previously measured Ta i lifetimes to determine accurate absolute transition probabilities. An experimental determination of the strength of possible infrared branches indicates that no significant infrared branches have been omitted.