Photofragmentation of third-row hydrides following photoexcitation at deep-core levels

Abstract

The relaxation dynamics of HCl, DCl, H 2 S, and D 2 S following photoexcitation in the vicinities of the Cl and S K-shell thresholds (ϳ2.8 keV for Cl, ϳ2.5 keV for S͒ were studied by means of ion time-of-flight mass spectroscopy. In all cases, the onset of pre-edge core-shell photoionization precedes the formation on resonance of a significant amount of neutral hydrogen as well as postcollision-interaction effects above threshold. Examination of the width of the H ϩ peak in spectra taken with the analyzer parallel and perpendicular to the polarization vector of the incident light indicates that on resonance, the photofragmentation asymmetry parameter, ␤, is approximately two for HCl, and is clearly positive for H 2 S. ͓S1050-2947͑98͒08211-0͔

State-selective enhanced production of positive ions and excited neutral fragments of gaseous CH2Cl2following ClLu1, Chen2, Lee3 et al. 2010Phys. Rev. A

“…The 2h1e or mhme state dissociates to produce the excited-state fragments before the excited Rydberg electron can relax. Similar observations are reported for several small molecules following core-level excitation [16,[49][50][51][52]. The detection of excited neutral fragments is demonstrated to be a sensitive probe for an investigation of shake-modified resonant Auger decay embedded in core-shell ionization continua, and PCI dynamics [49][50][51][52][53].…”

Magnetoresistance in Inclined Thin Magnetic Films

“…Similar observations have been reported for several small molecules following core-level excitation [26,27,40,44,67,68]. Especially noteworthy from figure 1 is that prominently produced anion yields of Cl − and Si − are observed in the shape-resonance region of the Cl 2p edge of gaseous SiCl 4 , analogous to other large molecules (e.g.…”

“…This is due to the fact that the wave function of a diffuse Rydberg electron has small overlap with that of the molecular-ion core and consequently the 2h1e or mhme states dissociate to produce the excited-state fragments before the excited Rydberg electron can relax. The detection of excited neutral particles and anion fragments has been demonstrated to be a sensitive probe for the investigation of the shake-modified resonant Auger decay and PCI dynamics [27,28,43,46,67,68]. Fluorescence emission was also observed to be a sensitive probe of the doubly excited states and coreionized/core-excited shake-up states [45,69].…”

“…This PCI manifests itself through a modified Auger line shape and energy shifts in the photoemission spectra, and through trends in ion-yield spectra. Although this effect has been investigated extensively and is well understood for free atoms [16]- [23], little research has been conducted on molecules [24]- [27]. Little is known about the formation of anions of core-excited molecules mediated by the PCI effect [28]- [38].…”

Sulfur K-edge photofragmentation of ethylene sulfide

“…Calibration at the S 1s-edge was performed by comparison to Reynaud et al 19 using the S ͑1s͒ −1 → 6t u transition in SF 6 at 2486.0 eV. 22,23 A sample time-of-flight spectrum is shown in Fig. 22,23 A sample time-of-flight spectrum is shown in Fig.…”