RESEARCH
NO2 Isotopologue Spectroscopy
Please enter 'PSI' for access to the protected PDF file.

We continue to collaborate with Prof. Remy Jost, of the Universite Joseph Fourier-CNRS Spectrométrie Physique in Grenoble, France investigating the role of isotopic symmetry in the energy spectrum. Our published results determined the zero point energy shift for six isotopologues of NO2 (click here for PDF) and calculated the ZPE shift for several triatomic molecules. We also evaluated the how symmetry impacts the density of states by determining the density differences between symmetric and asymmetric NO2 isotopologues (see it here). We found ~ 10% more rovibronic states in the asymmetric molecule relative to the symmetric configuration. It has been suggested that additional number of bound states gives high energy, asymmetric molecules a longer lifetime allowing them to be more effectively quenched to the ground state. It has been hypothesized that his mechanism is the origin of mass-independent fractionations (MIF). Our current work is to determine whether MIF occurs in NO2 formation/decomposition reactions



Laser induced fluorescence (LIF) set up at Universite Joseph Fourier. A lambda physics Ar laser (upper) exciting a Ti-Sapphire laser (lower) to generate high intensity, tuneable light in the 800 nm range.

Light from the Ti-Saph laser passes through a frequency doubler (top) resulting in tunable light near the ~ 420 nm dissociation limit of NO2. The laser beam is directed through a super sonic jet cooled beam of NO2. Cooling eliminates rotational energy. NO2 absorbs and is excited by the light, and the fluoresces further down in the expansion chamber, and this light is detected and recorded by a photo-muliplier tube that is perpendicular to the jet.