# Photodissociation and Infrared Spectroscopy of U+(CO2) n , UO+(CO2) n , and UO2+(CO2) n Cation-Molecular Complexes

## TL;DR

Scientists used laser techniques to study how uranium and its oxides bind with carbon dioxide molecules, revealing structural details about these complexes.

## Contribution

The study provides new insights into the coordination and vibrational properties of uranium-based cation-molecular complexes with CO2.

## Key findings

- CO2 ligands remain intact in the complexes, as shown by photodissociation patterns.
- An eight-coordinate structure is supported for the UO2+(CO2)8 complex based on vibrational spectroscopy.
- No evidence was found for the formation of oxide-carbonyl or oxalate species in the studied frequency range.

## Abstract

Laser vaporization
of uranium in a pulsed supersonic expansion
of carbon dioxide is used to produce complexes of the form U+(CO2)
n
, UO+(CO2)
n
, and UO2+(CO2)
n
. These ions are selected in
a reflectron time-of-flight mass spectrometer and studied with visible
laser photodissociation and tunable infrared laser photodissociation
spectroscopy in the region of the CO2 antisymmetric stretch.
The dissociation patterns and spectroscopy of these ions indicate
that CO2 ligands are intact molecules. Although reaction
products that form oxide-carbonyl or oxalate species are predicted
to be stable, there is no direct evidence in the frequency range studied
for the formation of these species. There is no clear indication for
the coordination numbers for singly charged uranium and its oxide
complexes with CO2. However, there is strong support in
the vibrational patterns for an eight-coordinate complex of the doubly
charged UO2+ species, i.e., UO2+(CO2)8.