THE NITROGEN LASER INDUCED FLUORESCENCE OF ACETALDEHYDE VAPOR ITS QUENCHING BY A MAGNETIC FIELD

Abstract

Nitrogen laser radiation at 3371 {\AA} excites the A state of acetaldehyde, generating fluorescence which appears as a complex system of discrete bands superimposed on a broad continuum. the spectrum extends from the laser wavelength to beyond 5200 {\AA}, peaking at 4200{\AA}. When a copper hollow cathode lamp with lines at 3247 and 3273 {\AA} is used for excitation, the fluorescence shifts to the blue and the details of the discrete structure change. Clearly the fluorescence cannot be interpreted as arising solely from the lowest vibrational level of A as previously assumed. A magnetic field is observed to quench about 30% of the laser induced fluorescence. The quenching is half complete (15%) at 600 G and appears pressure independent in the range 12 to 1000 mtorr. The magnetic quenching of acetaldehyde is compared to that observed for other molecules and possible quenching mechanisms are discussed.