Jahn-Teller distortions in the radical cations of cyclopropane and allene

1970 ◽  
Vol 7 (4) ◽  
pp. 428-430 ◽  
Author(s):  
E. Haselbach
Keyword(s):  
Radical Cations ◽  
Jahn Teller

Description of Bond Pseudorotation, Bond Pseudolibration, and Ring Pseudoinversion Processes Caused by the Pseudo-Jahn–Teller Effect: Fluoro Derivatives of the Cyclopropane Radical Cation

2014 ◽  
Vol 67 (3) ◽  
pp. 435 ◽  
Author(s):  
Wenli Zou ◽  
Dieter Cremer
Keyword(s):  
Radical Cation ◽  
Positive Charge ◽  
Radical Cations ◽  
Molecular Geometry ◽  
Teller Effect ◽  
Curvilinear Coordinates ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Derivatives Of ◽  
Fluoro Derivatives

Curvilinear coordinates are used to describe the molecular geometry and the pseudo-Jahn–Teller surface of F-substituted cyclopropane radical cations using the equation-of-motion coupled cluster EOMIP-CCSD/cc-pVTZ approach. The monofluoro derivative 2 undergoes bond pseudolibration (incomplete bond pseudorotation) between two symmetry-equivalent biradicaloid forms separated by a barrier of 2.2 kcal mol–1 (1 kcal mol–1 = 4.186 kJ mol–1) at low temperature. Bond pseudorotation and ring pseudoinversion have barriers of 12.1 and 16.5 kcal mol–1 respectively. The relative energies of 2 are affected by the distribution of the positive charge in the C3 ring and the formation of a CF bond with partial π character. There is a change of the CF bond length from 1.285 to 1.338 Å along the bond pseudorotation path. The changes of the CF bond outweigh the deformation effects of the C3 ring; however, both are a result of the pseudo-Jahn–Teller effect according to an (A′ + A′′) ⊗ (a′ + a′′) interaction. For the pentafluoro derivative 3 of the cyclopropane radical cation, bond pseudorotation has a barrier of 16.3 kcal mol–1 whereas ring pseudoinversion is hindered by a barrier of 21.7 kcal mol–1. Radical cation 3 is the first example of a trimethylene radical cation.

scholarly journals Table-Top X-ray Spectroscopy of Benzene Radical Cation

2020 ◽  
Author(s):  
Michael Epshtein ◽  
Valeriu Scutelnic ◽  
Zheyue Yang ◽  
Tian Xue ◽  
Marta L. Vidal ◽  
...  
Keyword(s):  
Transient Absorption ◽  
High Harmonic ◽  
Radical Cations ◽  
Spin Coupling ◽  
X Rays ◽  
X Ray ◽  
Two Photon ◽  
Jahn Teller ◽  
Theoretical Paper ◽  
High Level

<p></p><p>Ultrafast table-top x-ray spectroscopy <a>at the carbon K-edge </a>is used to measure the x-ray spectral features of benzene <a>radical cations (Bz<sup>+</sup>). The ground state of the cation is prepared selectively by </a><a>two-photon ionization of neutral benzene, and the x-ray spectra are probed at early times after the ionization by transient absorption using x-rays produced by high harmonic generation (HHG). </a><a>Bz<sup>+</sup> is well known to undergo Jahn-Teller </a>distortion, leading to a lower symmetry and splitting of the π orbitals. Comparison of the x-ray absorption spectra of the neutral and the cation reveals a splitting of the two degenerate π* orbitals as well as an appearance of a new peak due to excitation to the partially occupied π -subshell. The <a>π*</a> orbital splitting of the cation, elucidated on the basis of high-level calculations in a companion theoretical paper [Vidal et al, submitted to J. Phys. Chem. Lett.; ChemRxiv link: doi XXXXX], is discovered to be due to both the symmetry distortion and even more dominant spin coupling of the unpaired electron in the partially vacant π orbital (from ionization) with the unpaired electrons resulting from the transition from the 1s<sub>C</sub> core orbital to the fully vacant <a>π* </a>orbitals.</p><br><p></p>

Isotope effect on the static distortion and the dynamics of partially deuteriated Jahn-Teller active radical cations: cyclopropane-1,1-d2

1989 ◽  
Vol 93 (18) ◽  
pp. 6642-6645 ◽  
Author(s):  
K. Matsuura ◽  
K. Nunome ◽  
M. Okazaki ◽  
K. Toriyama ◽  
M. Iwasaki
Keyword(s):  
Isotope Effect ◽  
Radical Cations ◽  
Jahn Teller ◽  
Static Distortion

scholarly journals Table-Top X-ray Spectroscopy of Benzene Radical Cation

2020 ◽  
Author(s):  
Michael Epshtein ◽  
Valeriu Scutelnic ◽  
Zheyue Yang ◽  
Tian Xue ◽  
Marta L. Vidal ◽  
...  
Keyword(s):  
Transient Absorption ◽  
High Harmonic ◽  
Radical Cations ◽  
Spin Coupling ◽  
X Rays ◽  
X Ray ◽  
Two Photon ◽  
Jahn Teller ◽  
Theoretical Paper ◽  
High Level

<p></p><p>Ultrafast table-top x-ray spectroscopy <a>at the carbon K-edge </a>is used to measure the x-ray spectral features of benzene <a>radical cations (Bz<sup>+</sup>). The ground state of the cation is prepared selectively by </a><a>two-photon ionization of neutral benzene, and the x-ray spectra are probed at early times after the ionization by transient absorption using x-rays produced by high harmonic generation (HHG). </a><a>Bz<sup>+</sup> is well known to undergo Jahn-Teller </a>distortion, leading to a lower symmetry and splitting of the π orbitals. Comparison of the x-ray absorption spectra of the neutral and the cation reveals a splitting of the two degenerate π* orbitals as well as an appearance of a new peak due to excitation to the partially occupied π -subshell. The <a>π*</a> orbital splitting of the cation, elucidated on the basis of high-level calculations in a companion theoretical paper [Vidal et al, submitted to J. Phys. Chem. Lett.; ChemRxiv link: doi XXXXX], is discovered to be due to both the symmetry distortion and even more dominant spin coupling of the unpaired electron in the partially vacant π orbital (from ionization) with the unpaired electrons resulting from the transition from the 1s<sub>C</sub> core orbital to the fully vacant <a>π* </a>orbitals.</p><br><p></p>

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