Infrared spectroscopy at 20,000 scans per second. 
Improvements in a rapid scan ir spectrometer used for flash photolysis-kinetic spectroscopy are described.  The scanning mechanism now regularly operates at a repetition rate of 20,000 scans/sec; the photolysis flash has a half-time of 7.5 microsec, with energy up to 2940 J, and at 1500 J it yields 5 x 10(18) quanta/flash; the spectroscopic light source operates with a brightness temperature of 2400 K. The relationship between spectral resolution and scanning speed is quantitatively discussed.