The answer to yesterday's puzzler is CH, the free radical, whose fluorescent emission makes flames look blue. The spectrum below is from a butane torch flame. The CH dominates in the blue (~400 - 500 nm) with some contribution from the blue-green Swan bands of C2. More about that below. Contrary to the otherwise pretty great video that won the flame prize, the blue color at the bottom of the flame is not atomic emission.
There is a lot to learn from flame chemistry and it has real consequences for optimizing all sorts of engines and industrial processes. The US DOE has established several laboratories for this, among which the best, IEHO, is the Combustion Research Facility at Sandia, CA. Eli is greatly in favor of efficiency.
Rabett Run will be returning to this theme several times this week to discuss other flaming issues. (NONONO not that kind of flame, candle flames)