Isotope effects � i.e., the changes in molecular properties upon the substitution of one isotope of an element for another � can be used to refine our understanding of absorption, photoionization, and photodissociation spectra, as well as provide benchmarks for theoretical calculations. We present measurements conducted at the Advanced Light Source at Lawrence Berkeley National Laboratory of the photoionization of N2 (i.e., N2+h??N+N++e- and N2+h??N2++e-) for its three stable isotopologues, 14N2, 15N14N, and 15N2, between 15 and 26 eV. We use the measured isotope shifts to resolve controversial spectral peak assignments, including a shift of 0.015�0.0065 eV for the peak at 15.677 eV in the 14N2 spectrum that rules out assignment to b'1Su+v'=44 and supports assignment to (A2?uv'=2)4ssg 1?u. In addition, these newly measured isotope shifts can now be incorporated into models of planetary atmospheres and interstellar environments to constrain chemical histories and pathways based on observations of nitrogen isotopic compositions.

Isotope effects and spectroscopic assignments in the photoionization spectrum of N<sub>2</sub>

243rd National Meeting (2012)

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Isotope effects and spectroscopic assignments in the photoionization spectrum of N2

Isotope effects and spectroscopic assignments in the photoionization spectrum of N₂