Resonance Enhanced Photodissociation Spectroscopy Of Auag+ Reveals Isotopic Dependance On Photodissociation

Marlton, Samuel Jack Palmer

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https://hdl.handle.net/2142/116693 Copy

Description

Title

Resonance Enhanced Photodissociation Spectroscopy Of Auag+ Reveals Isotopic Dependance On Photodissociation

Author(s)

Marlton, Samuel Jack Palmer

Contributor(s)

• Bieske, Evan
• Buntine, Jack T.
• Watkins, Patrick
• Liu, Chang

Issue Date

2022-06-21

Keyword(s)

Photodissociation and photochemistry

Abstract

\begin{wrapfigure}{l}{0pt} \includegraphics[scale=0.8]{agau_two_exp_spectra_3.eps} \end{wrapfigure} Bimetallic materials comprised of gold and silver have useful optical and electronic properties, which are complicated by quantum mechanical, relativistic, and isotopic effects. To provide a bottom-up perspective on these larger systems, the smallest monocation comprised of gold and silver---diatomic AuAg+---is spectroscopically probed using resonance enhanced photodissociation (REPD). The $^{197}$Au$^{107}$Ag$^{+}$ and $^{197}$Au$^{109}$Ag$^{+}$ isotopologues are confined in a cryogenically cooled (ca. 5 K) quadrupole ion trap and are exposed to tunable light while detecting Au+ photofragment ions using a time-of-flight mass spectrometer. Electronic spectra in the UV exhibit a transition from the X$^{2}$$\Sigma$$^{+}_{1/2}$ ground state to an excited state that is yet to be assigned. Vibronic progressions for this transition extend over more than 30 quanta for both isotopologues, but with striking differences in band intensities (see Figure). This difference in photodissociation yield between the two isotopologues arises because the vibronic energies and associated wavefunctions depend on the reduced mass, leading to a difference in the coupling of the excited state levels and the repulsive electronic state that leads to dissociation. The observed photodissociation intensities for $^{197}$Au$^{107}$Ag$^{+}$ and $^{197}$Au$^{109}$Ag$^{+}$ are successfully modelled by calculating respective vibronic energies and wavefunctions of their bound and dissociative electronic states.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Handle URL

https://hdl.handle.net/2142/116693

DOI

https://doi.org/10.15278/isms.2022.TJ01

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Copyright 2022 held by the authors

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