2008 Articles

Singlet molecular oxygen by direct excitation

Jockusch, Steffen; Turro, Nicholas J.; Thompson, Elizabeth K.; Gouterman, Martin; Callis, James B.; Khalil, Gamal E.

Direct excitation at 1064 nm and detection of singlet molecular oxygen at 1270 nm is made possible by the availability of powerful YAG-lasers and sensitive NIR photomultipliers. Singlet oxygen was generated in condensed phase at 77 K by direct excitation at 1064 nm (without the use of sensitizers). Several luminescing species were observed by time resolved luminescence spectroscopy and luminescence lifetime measurements, including the single molecule 1Δgand 1Σg+states as well as luminescence from the [1Δg]2 simultaneous transition. As an application we propose a novel method for obtaining quantitative non-intrusive mapping of the 2-D oxygen concentrations and pressure at cryogenic temperatures, which is of importance in aircraft design for high altitudes.