Dynamics of dissociative photodetachment in cluster anions: O4- and O2-H2O

摘要

Abstract: A preliminary report is presented on experiments using fast ion-beam translational energy spectroscopy to study dissociative photodetachment and photodissociation dynamics in the small cluster ions O$-4$/$+$MIN$/ and O$-2$/$+$MIN$/$DOT@(H$-2$/O). Translational energy and angular distributions of coincident molecular fragments were recorded from the photodestruction of O$-4$/$+$MIN$/ and O$-2$/$+$MIN$/$DOT@(H$-2$/O) at 523, 349, and 262 nm. At each wavelength, the O$-4$/$+$MIN$/ results confirm the existence of at least two distinct channels: dissociative photodetachment (O$-4$/$+$MIN$/ $PLU h$nu $YLD O$-2$/ $PLU O$-2$/ $PLU e$+$MIN$/) and photodissociation (O$-4$/$+$MIN$/ $PLU h$nu $YLD O$-2$/ $PLU O$-2$/$+$MIN$/). Observation of strongly anisotropic angular distributions shows that dissociation occurs on the time-scale of molecular rotation in both processes. The photodissociation of O$-4$/$+$MIN$/ at 523 nm gives a new value for the O$-2$/-O$-2$/$+$MIN$/ bond energy, D$-O$/ $EQ 0.39 $POM 0.05 eV. In O$- 2$/$+$MIN$/$DOT@(H$-2$/O), a single dissociative photodetachment channel (O$- 2$/$+$MIN$/$DOT@(H$-2$/O) $PLU h$nu $YLD O$-2$/ $PLU H$-2$/O $PLU e$+$MIN$/) is observed at all wavelengths. Angular distributions from this process are slightly anisotropic and exhibit a small wavelength dependence. !52