1. the branch of chemistry that studies elementary (often very fast) chemical reactions as they occur; the experimental methods are often based on the use of femtosecond laser pulses;
WordNet (r) 3.0 (2006):
femtochemistry
n 1: the branch of chemistry that studies elementary (often very
fast) chemical reactions as they occur; the experimental
methods are often based on the use of femtosecond laser
pulses