Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 2 of 2

Full-Text Articles in Physical Sciences and Mathematics

Microwave Regeneration And Thermal And Oxidative Stability Of Imidazolium Cyanopyrrolide Ionic Liquid For Direct Air Capture Of Carbon Dioxide, Yun-Yang Lee, Eda Cagli, Aidan Klemm, Ruth Dikki May 2023

Microwave Regeneration And Thermal And Oxidative Stability Of Imidazolium Cyanopyrrolide Ionic Liquid For Direct Air Capture Of Carbon Dioxide, Yun-Yang Lee, Eda Cagli, Aidan Klemm, Ruth Dikki

Faculty Scholarship

Understanding the oxidative and thermal degradation of CO2 sorbents is essential for assessing long-term sorbent stability in direct air capture (DAC). The potential degradation pathway of imidazolium cyanopyrrolide, an ionic liquid (IL) functionalized for superior CO2 capacity and selectivity, is evaluated under accelerated degradation conditions to elucidate the secondary reactions that can occur during repetitive absorption-desorption thermal-swing cycles. The combined analysis from various spectroscopic, chromatographic, and thermal gravimetric measurements indicated that radical and SN2 mechanisms in degradation are encouraged by the nucleophilicity of the anion. Thickening of the liquid and gas evolution are accompanied by 50 % reduction in CO2 …


Minimal Auxiliary Basis Set Approach For The Electronic Excitation Spectra Of Organic Molecules, Zehao Zhou, Shane M. Parker Feb 2023

Minimal Auxiliary Basis Set Approach For The Electronic Excitation Spectra Of Organic Molecules, Zehao Zhou, Shane M. Parker

Faculty Scholarship

We report a minimal auxiliary basis model for time-dependent density functional theory (TDDFT) with hybrid density functionals that can accurately reproduce excitation energies and absorption spectra from TDDFT while reducing cost by about \change{two} orders of magnitude. Our method, dubbed TDDFT-ris, employs the resolution-of-the-identity technique with just one $s$-type auxiliary basis function per atom for the linear response operator, where the Gaussian exponents are parametrized across the periodic table using %using tabulated atomic radii with a single global scaling factor. By tuning on a small test set, we determine a single functional-independent scale factor that balances errors in excitation energies …