PFI-ZEKE photoelectron and high resolution photoionization spectra of ND₃ with MQDT simulations

Abstract

The rotationally resolved PFI-ZEKE (pulsed-field ionization zero-kinetic energy) photoelectron spectrum of ND₃ has been recorded at the = 0, 1 and 2 thresholds, by single-photon VUV excitation from the ground-state. An assignment of the ← spectrum is presented, allowing a determination of the adiabatic ionization potential of ND₃ (82261.7(15) cm⁻¹) and of the rotational constants and positions of the = 0, 1 and 2 vibrational levels of the ion. These parameters are used in a multichannel quantum defect theory (MQDT) simulation of the high-resolution photoionization spectrum in the range 82100–83300 cm⁻¹ [R. Seiler et al., J. Chem. Phys. 118, 10024 (2003).]. A good simulation and an assignment of around 80% of the lines of the ND₃ photoionization spectrum are achieved, verifying the validity of the molecular constants derived from the PFI-ZEKE photoelectron spectrum and also the quantum defect parameters derived from ab initio calculations.

Keywords:

• ZEKE spectroscopy
• Rydberg spectroscopy
• multichannel quantum defect theory

Acknowledgements

We are grateful for financial support of this work to the Swiss National Science Foundation (project No 200020-125030), to the Petroleum Research Fund of the American Chemical Society, and to the Engineering and Physical Sciences Research Council.