Laser Photodetachment Threshold Spectroscopy on O−, Ag−, PdO− and AgO−

Abstract

The aim of this thesis is to investigate the possibility of using anionic oxides in selective laser photodetachment suppression of 107Ag in Accelerator Mass Spectrometry (AMS) studies of 107Pd. The thesis will also give a brief theoretical introduction to negative ions, some general information about AMS and the connection to radiometric dating, and an overview description of Gotheburg University Negative Ion Laser LAboratory (GUNILLA).

Laser Photodetachment Threshold Spectroscopy (LPTS) was performed on O−, Ag−, PdO− and AgO− to compare the photodetachment cross section behaviours of the anionic silver and palladium oxides and see if you at some laser wavelength can neutralize AgO− while keeping PdO− negatively charged. The results show that the photodetachment cross section of PdO− relatively tightly follows that of AgO− in the investigated laser wavelenght interval [900 nm - 700 nm] making it impossible to only detach electrons from AgO−. The conclusion drawn from this is that AgO− and PdO− are not suitable molecular candidates for selective laser photodetachment suppression of 107Ag in AMS studies of 107Pd.

The project, though having negative results in the sense of not finding a molecular system fulfilling the properties sought in the AMS application, are not considered unsuccessful. The project experiments are seen as a necessary and successfully investigated stepping stone in the search for an easily created molecular system making selective laser photodetachment suppression of 107Ag in AMS studies of 107Pd possible. The proposed next step is to investigate the photodetachment cross section behaviours of silver and palladium dioxides and fluorides.