With the lifetime of charged pions being approximately 26 nanoseconds (recall that the speed of light is approx. 1 foot /
nanosecond), there is still a "workable" amount of time using them to do "chemistry."
Here are some useful online papers/references to Hadronic Atoms, namely Pionic Hydrogen/Deuterium (in addition to those already
uncovered by others, here):
http://arxiv.org/pdf/0705.3965.pdf
http://www.radiochem.org/paper/JN11/j011Shinohara.pdf
http://www.sciencedirect.com/science/article/pii/S0375947497004661
http://www.physics.adelaide.edu.au/cssm/workshops/60-fest-talks/Phillips.pdf
- Mark Jurich
