Knowledge Bank

We report photoelectron spectra of IBr$\mathrm{<mrow\; data-mjx-texclass="ORD">-</mrow>}$(CO$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$) to understand the changes in IBr$\mathrm{<mrow\; data-mjx-texclass="ORD">-</mrow>}$ structure due to clustering. These experiments utilize anion photoelectron spectroscopy combined with velocity map imaging (VMI) to obtain photoelectron energy and angular distributions. Photodetachment of IBr$\mathrm{<mrow\; data-mjx-texclass="ORD">-</mrow>}$(X$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}\Sigma +$) with 300 nm radiation accesses three neutral states of IBr: the ground state (X$\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}\Sigma +$) and the next two excited states ($\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}\Pi 2$ and $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}\Pi 1$). Known excitation energies between the neutral states allow a direct calculation of the EA of IBr, 2.53 eV. Observed vibrational progressions resulting from transitions to the excited 3$\Pi$ states of IBr lead to equilibrium distances. Current experiments on IBr$\mathrm{<mrow\; data-mjx-texclass="ORD">-</mrow>}$(CO$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$) will be compared to that of the bare anion to understand changes in the structure of the cluster with additional CO$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$ molecules.