scholarly journals Geometrical Reorganization of a Methane Cation upon a Sudden Ionization: An Isotope Effect in Electronic Non Equilibrium Quantum Dynamics

2021 ◽  
Author(s):  
Cayo Gonçalves ◽  
Raphael D. Levine ◽  
Francoise Remacle
Keyword(s):  
Isotope Effect ◽  
Ground State ◽  
Quantum Dynamics ◽  
High Harmonic ◽  
Electronic States ◽  
Structural Rearrangement ◽  
Experimental Measurements ◽  
Strongly Coupled ◽  
Jahn Teller ◽  
Electronic Coherence

<p>An ultrafast structural, Jahn-Teller (JT) driven, electronic coherence mediated quantum dynamics in the CH<sub>4</sub><sup>+</sup> and CD<sub>4</sub><sup>+ </sup>cations that follows a sudden ionization by an XUV attopulse, exhibits a strong isotope effect. The JT effect makes the methane cation unstable in the T<sub>d</sub> geometry of the neutral. Upon the sudden ionization the cation is produced in a coherent superposition of three electronic states that are strongly coupled. On the ground state of the cation the few femtosecond structural rearrangement leads first to a geometrically less distorted D<sub>2d</sub> minimum followed by a reorganization to a shallow C<sub>2v</sub> minimum. The dynamics is computed for an ensemble of 8000 ions randomly oriented with respect to the polarization of the XUV pulse. The ratio, about 3, of the CD<sub>4</sub><sup>+</sup> and CH<sub>4</sub><sup>+</sup><sub> </sub>autocorrelation functions, is in agreement with experimental measurements of the high harmonic spectra. The high value of the ratio is attributed to the faster electronic coherence dynamics in CH<sub>4</sub><sup>+</sup>. </p>

scholarly journals Geometrical Reorganization of a Methane Cation upon a Sudden Ionization: An Isotope Effect in Electronic Non Equilibrium Quantum Dynamics

2021 ◽  
Author(s):  
Cayo Gonçalves ◽  
Raphael D. Levine ◽  
Francoise Remacle
Keyword(s):  
Isotope Effect ◽  
Ground State ◽  
Quantum Dynamics ◽  
High Harmonic ◽  
Electronic States ◽  
Structural Rearrangement ◽  
Experimental Measurements ◽  
Strongly Coupled ◽  
Jahn Teller ◽  
Electronic Coherence

<p>An ultrafast structural, Jahn-Teller (JT) driven, electronic coherence mediated quantum dynamics in the CH<sub>4</sub><sup>+</sup> and CD<sub>4</sub><sup>+ </sup>cations that follows a sudden ionization by an XUV attopulse, exhibits a strong isotope effect. The JT effect makes the methane cation unstable in the T<sub>d</sub> geometry of the neutral. Upon the sudden ionization the cation is produced in a coherent superposition of three electronic states that are strongly coupled. On the ground state of the cation the few femtosecond structural rearrangement leads first to a geometrically less distorted D<sub>2d</sub> minimum followed by a reorganization to a shallow C<sub>2v</sub> minimum. The dynamics is computed for an ensemble of 8000 ions randomly oriented with respect to the polarization of the XUV pulse. The ratio, about 3, of the CD<sub>4</sub><sup>+</sup> and CH<sub>4</sub><sup>+</sup><sub> </sub>autocorrelation functions, is in agreement with experimental measurements of the high harmonic spectra. The high value of the ratio is attributed to the faster electronic coherence dynamics in CH<sub>4</sub><sup>+</sup>. </p>

Ultrafast geometrical reorganization of a methane cation upon a sudden ionization: An isotope effect in electronic non equilibrium quantum dynamics

2021 ◽  
Author(s):  
Cayo C. M. Goncalves ◽  
Raphael D. Levine ◽  
Francoise Remacle
Keyword(s):  
Isotope Effect ◽  
Quantum Dynamics ◽  
Jahn Teller ◽  
Electronic Coherence ◽  
Non Equilibrium

An ultrafast structural, Jahn-Teller (JT) driven, electronic coherence mediated quantum dynamics in the CH4+ and CD4+ cations that follows a sudden ionization by an XUV attopulse, exhibits a strong isotope...

The photoelectron spectrum of sulphur trioxide: Jahn-Teller distortion in SO + 3

1974 ◽  
Vol 336 (1606) ◽  
pp. 355-364 ◽  
Keyword(s):  
Experimental Data ◽  
Ground State ◽  
Photoelectron Spectrum ◽  
Electronic States ◽  
Teller Distortion ◽  
Definite Evidence ◽  
Spin Resonance ◽  
Jahn Teller ◽  
Sulphur Trioxide ◽  
Jahn Teller Distortion

The photoelectron spectrum of sulphur trioxide has been recorded and extensive fine structure resolved. In three bands of the spectrum there is evidence for Jahn-Teller distortion. This has been interpreted quantitatively using the model of Longuet-Higgins, Opik, Pryce & Sack (1958). It also provides definite evidence that the three bands correspond to degenerate electronic states of SO + 3 . Four ionization potentials were found with values 12.8, 13.8, 14.9 and 17.9 eV. In two cases approximate changes in the S—O bond length have been calculated from the experimental data. The order of the first three electronic states of SO + 3 is unexpected, the ground state being degenerate. This result is compared with other data from photoelectron, ultraviolet and electron spin resonance spectra of isoelectronic species.

Vibronically induced Jahn–Teller progressions in the electronic spectrum of iridium hexafluoride

1968 ◽  
Vol 46 (15) ◽  
pp. 1721-1724 ◽  
Author(s):  
J. C. D. Brand ◽  
G. L. Goodman
Keyword(s):  
Electronic Spectrum ◽  
Excited States ◽  
Electric Dipole ◽  
Ground State ◽  
Electronic States ◽  
Electronic Transitions ◽  
Electrostatic Forces ◽  
First Approximation ◽  
Jahn Teller

The absorption of IrF6 vapor between 0.7 and 1.3 μ consists of three distinct electronic transitions connecting the Γ8g ground state with higher Γ6g, Γ8g, and Γ7g states of the (5d f2g)3 configuration. In first approximation, Jahn–Teller forces vanish in the two Γ8g states, while the Γ6g and Γ7g states involve Kramers magnetic degeneracy, which cannot be split by electrostatic forces. Accordingly, no splittings of the ν2(eg) or ν5(f2g) excited states are observed in these spectra, but short progressions in ν5 do appear in the electric-dipole-allowed, vibronic parts of these transitions. These progressions are considered to show that Jahn–Teller anharmonicity can be induced by admixtures of odd-parity, orbitally degenerate electronic states, i.e. by the same mechanism through which these transitions derive their electric-dipole intensity.

The Jahn–Teller effect in the lower electronic states of benzene cation. III. The ground-state vibrations of C6H6+ and C6D6+

2004 ◽  
Vol 120 (18) ◽  
pp. 8587-8599 ◽  
Author(s):  
Andrew B. Burrill ◽  
You K. Chung ◽  
Heather A. Mann ◽  
Philip M. Johnson
Keyword(s):  
Ground State ◽  
Electronic States ◽  
Teller Effect ◽  
Jahn Teller ◽  
Jahn Teller Effect

The Interplay of Open-Shell Spin-Coupling and Jahn-Teller Distortion in Benzene Radical Cation Probed by X-ray Spectroscopy

2020 ◽  
Author(s):  
Marta L. Vidal ◽  
Michael Epshtein ◽  
Valeriu Scutelnic ◽  
Zheyue Yang ◽  
Tian Xue ◽  
...  
Keyword(s):  
High Harmonic ◽  
Open Shell ◽  
Spin Coupling ◽  
High Symmetry ◽  
Teller Distortion ◽  
Spectral Window ◽  
X Ray ◽  
Jahn Teller ◽  
X Ray Absorption ◽  
Jahn Teller Distortion

We report a theoretical investigation and elucidation of the x-ray absorption spectra of neutral benzene and of the benzene cation. The generation of the cation by multiphoton ultraviolet (UV) ionization as well as the measurement of<br>the carbon K-edge spectra of both species using a table-top high-harmonic generation (HHG) source are described in the companion experimental paper [M. Epshtein et al., J. Phys.<br>Chem. A., submitted. Available on ChemRxiv]. We show that the 1sC -> pi transition serves as a sensitive signature of the transient cation formation, as it occurs outside of the spectral window of the parent neutral species. Moreover, the presence<br>of the unpaired (spectator) electron in the pi-subshell of the cation and the high symmetry of the system result in significant differences relative to neutral benzene in the spectral features associated with the 1sC ->pi* transitions. High-level calculations using equation-of-motion coupled-cluster theory provide the interpretation of the experimental spectra and insight into the electronic structure of benzene and its cation.<br>The prominent split structure of the 1sC -> pi* band of the cation is attributed to the interplay between the coupling of the core -> pi* excitation with the unpaired electron<br>in the pi-subshell and the Jahn-Teller distortion. The calculations attribute most of<br>the splitting (~1-1.2 eV) to the spin coupling, which is visible already at the Franck-Condon structure, and estimate the additional splitting due to structural relaxation to<br>be around ~0.1-0.2 eV. These results suggest that x-ray absorption with increased resolution might be able to disentangle electronic and structural aspects of the Jahn-Teller<br>effect in benzene cation.<br>

ROTATIONAL ANALYSIS OF THE β BANDS OF PHOSPHORUS MONOXIDE

1959 ◽  
Vol 37 (2) ◽  
pp. 136-143 ◽  
Author(s):  
Nand Lal Singh
Keyword(s):  
Ground State ◽  
Band System ◽  
Electronic States ◽  
Rotational Analysis ◽  
Rotational Constants ◽  
Fine Structures ◽  
Π State

The fine structures of three of the β bands of PO which occur near 3200 Å have been analyzed. The analysis shows that the upper state of this band system is a 2Σ and not a 2Π state as previously believed. The rotational constants of both electronic states have been determined and it is found that the ground state constants, previously determined from the γ bands, are incorrect.

VUV FRAGMENTATION OF SOME HYDROFLUOROCARBON CATIONS STUDIED USING COINCIDENCE TECHNIQUES

2002 ◽  
Vol 09 (01) ◽  
pp. 153-158 ◽  
Author(s):  
WEIDONG ZHOU ◽  
D. P. SECCOMBE ◽  
R. Y. L. CHIM ◽  
R. P. TUCKETT
Keyword(s):  
Kinetic Energy ◽  
Ab Initio ◽  
Ground State ◽  
Lower Energy ◽  
Lone Pair ◽  
Electronic States ◽  
Photoelectron Spectra ◽  
Highest Occupied Molecular Orbital ◽  
Impulsive Model ◽  
Lone Pair Electrons

Threshold photoelectron–photoion coincidence (TPEPICO) spectroscopy has been used to investigate the decay dynamics of the valence electronic states of the parent cation of several hydrofluorocarbons (HFC), based on fluorine-substituted ethane, in the energy range 11–25 eV. We present data for CF 3– CHF 2, CF 3– CH 2 F , CF 3– CH 3 and CHF 2– CH 3. The threshold photoelectron spectra (TPES) of these molecules show a common feature of a broad, relatively weak ground state, associated with electron removal from the highest-occupied molecular orbital (HOMO) having mainly C–C σ-bonding character. Adiabatic and vertical ionisation energies for the HOMO of the four HFCs are presented, together with corresponding values from ab initio calculations. For those lower-energy molecular orbitals associated with non-bonding fluorine 2pπ lone pair electrons, these electronic states of the HFC cation decay impulsively by C–F bond fission with considerable release of translational kinetic energy. Appearance energies are presented for formation of the daughter cation formed by such a process (e.g. CF 3– CHF +), together with ab initio energies of the corresponding dissociation channel (e.g. CF 3– CHF + + F ). Values for the translational kinetic energy released are compared with the predictions of a pure-impulsive model.

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