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The electronic structure of ionic liquids based on the TFSI anion : A gas phase UPS and DFT study

Kuusik, Ivar; Kook, Mati; Pärna, Rainer LU ; Kivimäki, Antti LU ; Käämbre, Tanel LU ; Reisberg, Liis LU ; Kikas, Arvo and Kisand, Vambola (2019) In Journal of Molecular Liquids 294.
Abstract

The valence bands of [EMIM][TFSI], [DEME][TFSI] and [PYR1,4][TFSI] gas-phase ion pairs have been investigated using ultraviolet photoelectron spectroscopy (UPS). The photoelectron spectra are interpreted by using several density functional and ab initio calculation methods. Although the experimental vapor phase spectra are similar, the different calculation methods make different predictions about the HOMO molecular state of the ion-pairs of the ionic liquids. The HOMO state of the [DEME][TFSI] ion-pair is due to the TFSI anion, while in [EMIM][TFSI] it is due to the EMIM cation. However, it is difficult to make conclusive assignments for the [PYR1,4][TFSI] ionic liquid. All calculation methods predict the LUMO to... (More)

The valence bands of [EMIM][TFSI], [DEME][TFSI] and [PYR1,4][TFSI] gas-phase ion pairs have been investigated using ultraviolet photoelectron spectroscopy (UPS). The photoelectron spectra are interpreted by using several density functional and ab initio calculation methods. Although the experimental vapor phase spectra are similar, the different calculation methods make different predictions about the HOMO molecular state of the ion-pairs of the ionic liquids. The HOMO state of the [DEME][TFSI] ion-pair is due to the TFSI anion, while in [EMIM][TFSI] it is due to the EMIM cation. However, it is difficult to make conclusive assignments for the [PYR1,4][TFSI] ionic liquid. All calculation methods predict the LUMO to be of cationic origin in all the studied ion-pairs.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Molecular Liquids
volume
294
publisher
Elsevier
external identifiers
  • scopus:85070955019
ISSN
0167-7322
DOI
10.1016/j.molliq.2019.111580
language
English
LU publication?
yes
id
d611c76d-9b0d-4df4-bbf6-4db744d8eae3
date added to LUP
2019-09-09 10:55:40
date last changed
2019-09-26 04:41:50
@article{d611c76d-9b0d-4df4-bbf6-4db744d8eae3,
  abstract     = {<p>The valence bands of [EMIM][TFSI], [DEME][TFSI] and [PYR<sub>1,4</sub>][TFSI] gas-phase ion pairs have been investigated using ultraviolet photoelectron spectroscopy (UPS). The photoelectron spectra are interpreted by using several density functional and ab initio calculation methods. Although the experimental vapor phase spectra are similar, the different calculation methods make different predictions about the HOMO molecular state of the ion-pairs of the ionic liquids. The HOMO state of the [DEME][TFSI] ion-pair is due to the TFSI anion, while in [EMIM][TFSI] it is due to the EMIM cation. However, it is difficult to make conclusive assignments for the [PYR<sub>1,4</sub>][TFSI] ionic liquid. All calculation methods predict the LUMO to be of cationic origin in all the studied ion-pairs.</p>},
  articleno    = {111580},
  author       = {Kuusik, Ivar and Kook, Mati and Pärna, Rainer and Kivimäki, Antti and Käämbre, Tanel and Reisberg, Liis and Kikas, Arvo and Kisand, Vambola},
  issn         = {0167-7322},
  language     = {eng},
  publisher    = {Elsevier},
  series       = {Journal of Molecular Liquids},
  title        = {The electronic structure of ionic liquids based on the TFSI anion : A gas phase UPS and DFT study},
  url          = {http://dx.doi.org/10.1016/j.molliq.2019.111580},
  volume       = {294},
  year         = {2019},
}