Energy dependence of photoion rotational distributions of N_2 and CO

Abstract

We present the first measurements of rotational distributions for photoionization over extended energy ranges [0 ≤ E_k ≤ 200 eV for N_2 (2σ^(-1)_u) and of 3 ≤ E_k ≤ 125 eV for CO (4σ^(−1))]. The N_2 and CO results show a strikingly unusual and different energy dependence. Although differences are expected due to the absence of a center of symmetry in CO, detailed calculations reveal that this behavior arises from the presence of Cooper minima in the photoelectron continuum (kσ_g) in the case of N_2 and from an f-wave shape resonance for 4σ^(−1) photoionization in CO.

Additional Information

© 1994 American Physical Society. (Received 2 September 1993) The efforts of the CAMD staff are greatly appreciated, and we are particularly indebted to Dr. Volker Saile, Dr. John Scott, and Dr. Eizi Morikawa for their support with the plane grating monochromator. We also acknowledge support from NSF (CHE-9315857) and the Louisiana LEQSF program. Work at California Institute of Technology was supported by grants from the Air Force Office of Scientific Research and the Office of Health and Environmental Research of the U.S. Department of Energy. We also acknowledge the use of resources of the Jet Propulsion Laboratory/California Institute of Technology CRAY Y-MP2E/232 supercomputer.

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Published - PhysRevLett.72.44.pdf

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