Search

Describes the development of an efficient electron time-of-flight selection scheme for high resolution pulsed field ionization photoelectron (PFI-PE) measurements using monochromatized multibunch undulator synchrotron radiation at the Advanced Light Source. PFI-PE bands; Spectral analysis; Advantage of synchrotron based PFI-PE experiments.

We have obtained rotationally resolved pulsed-field ionization photoelectron (PFI-PE) spectra for O[sub 2] in the energy range of 17.05-18.13 eV, covering the ionization transitions O[sub 2][sup +](A [sup 2]Π[sub u],v[sup +]=0-12,N[sup +])←O[sub 2](X [sup 3]Σ[sub g][sup -],v[sup ″]=0,N[sup ″]). Although these O[sub 2][sup +](A [sup 2]Π[sub u],v[sup +]) PFI-PE bands have significant overlaps with vibrational bands for O[sub 2][sup +](a [sup 4]Π[sub u]) and O[sub 2][sup +](X [sup 2]Π[sub g]), we have identified all the O[sub 2][sup +](A [sup 2]Π[sub u],v[sup +]=0-12) bands by simulation of spectra obtained using supersonically cooled O[sub 2] samples with rotational temperatures approx. 20 and 220 K. While these v[sup +]=0-12 PFI-PE bands represent the first rotationally resolved photoelectron data for O[sub 2][sup +](A [sup 2]Π[sub u]), the PFI-PE bands for O[sub 2][sup +](A [sup 2]Π[sub u],v[sup +]=9 and 10) are the first rotationally resolved spectroscopic data for these levels. The simulation also allows the determination of accurate ionization energies, vibrational constants, and rotational constants for O[sub 2][sup +](A [sup 2]Π[sub u],v[sup +]=0-12). The analysis of the PFI-PE spectra supports the conclusion of the previous emission study that the O[sub 2][sup +](A [sup 2]Π[sub u],v[sup +]=9 and 10) states are strongly perturbed by a nearby electronic state. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We have obtained rotationally resolved pulsed field ionization-photoelectron (PFI-PE) spectra of O[sub 2] in the energy range of 16.0-18.0 eV, covering ionization transitions O[sub 2][sup +](a [sup 4]Π[sub u], v[sup +]=0-18,J[sup +])←O[sub 2](X [sup 3]Σ[sub g][sup .], v[sup ″]=0,N[sup ″]). Although these vibrational PFI-PE bands for O[sub 2][sup +](a [sup 4]Π[sub u], v[sup +]) have significant overlaps with those for O[sub 2][sup +](X [sup 2]Π[sub g]) and O[sub 2][sup +](A [sup 2]Π[sub u]), we have identified all O[sub 2][sup +](a [sup 4]Π[sub u], v[sup +]=0-18) bands by simulation of spectra obtained using supersonically cooled O[sub 2] samples with rotational temperatures approx. 20 and 220 K. While the v[sup +]=4-18PFI-PE bands represent the first rotationally resolved photoelectron data for O[sub 2][sup +](a [sup 4]Π[sub u]), the PFI-PE bands for O[sub 2][sup +](a [sup 4]Π[sub u], v[sup +]=10-18) are the first rotationally resolved spectroscopic data for these levels. The simulation also allows the determination of accurate ionization energies, vibrational constants, and rotational constants for O[sub 2][sup +](a [sup 2]Π[sub u], v[sup +]=0-18). The observed intensities of spin-orbit components for the majority of O[sub 2][sup +](a [sup 2]Π[sub u], v[sup +]) vibrational bands are in accordance with the forced spin-orbit/rotational autoionization mechanism. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Abstract: The comparison of rotationally resolved infrared–vacuum ultraviolet–pulsed field ionization–photoelectron (IR–VUV–PFI–PE) depletion and IR–VUV–photoion measurements of C2H4 has illustrated the difference of these two methods and the rotational nature of the IR–VUV–PFI–PE depletion method. The IR–VUV–photoion spectra of trans-2-butene in the region 2910–3000cm−1 observed at different delays between the IR and VUV lasers are also presented to show that the IR–VUV–PI method is potentially useful for the study of intramolecular vibrational redistributions (IVRs). For short IVR lifetimes of vibrationally excited polyatomic neutrals, the IR–VUV–PFI–PE depletion method can serve as an alternative of the IR–VUV–PI scheme for rotationally resolved IR spectroscopy measurements. [Copyright &y& Elsevier]