Valence electronic structure of [EMIM][B(CN)4]: Ion-pair vs. bulk description
: I. Kuusik, M. Berholts, J. Kruusma, A. Tõnisoo, E. Lust, E. Nõmmiste, V. Kisanda
Publisher: Royal Society of Chemistry
: 2019
: RSC Advances
: RSC Advances
: 9
: 57
: 33140
: 33146
: 7
: 2046-2069
: 2046-2069
DOI: https://doi.org/10.1039/c9ra06762k
: https://research.utu.fi/converis/portal/detail/Publication/43732673
The ultraviolet photoelectron spectrum of the [EMIM][B(CN)4] ionic liquid was recorded and analyzed. Together with different ab initio calculation methods, detailed insight into the electronic structure of this simple room temperature ionic liquid is possible. The ion-pair approximation to the liquid electronic structure was not sufficient. Therefore bulk ab initio calculations were performed on a proposed crystal structure. The modelling of bulk electronic spectra is able to explain the experimental electronic structure of the ionic liquid. Most notably, the dispersion corrected PBE calculation (PBE-D3BJ) showed good agreement with the experimental UPS spectrum. The spectra simulated by the B97-D and the BLYP-D3(BJ) functionals were also in agreement with the experimental data. The LDA approximation only provided qualitative agreement while the optB88-vdW and CX-vdW functionals were not good. However, it will be shown that many requirements have to be met in order to accurately describe the electronic structure of this ionic liquid.