scholarly journals Attosecond timing of electron emission from a molecular shape resonance

2020 ◽  
Vol 6 (31) ◽  
pp. eaba7762 ◽  
Author(s):  
S. Nandi ◽  
E. Plésiat ◽  
S. Zhong ◽  
A. Palacios ◽  
D. Busto ◽  
...  
Keyword(s):  
Potential Barrier ◽  
Molecular Spectroscopy ◽  
Molecular Shape ◽  
High Spectral Resolution ◽  
Shape Resonance ◽  
Nuclear Motion ◽  
Centrifugal Barrier ◽  
Ionization Time ◽  
Molecular Photoionization ◽  
Franck Condon

Shape resonances in physics and chemistry arise from the spatial confinement of a particle by a potential barrier. In molecular photoionization, these barriers prevent the electron from escaping instantaneously, so that nuclei may move and modify the potential, thereby affecting the ionization process. By using an attosecond two-color interferometric approach in combination with high spectral resolution, we have captured the changes induced by the nuclear motion on the centrifugal barrier that sustains the well-known shape resonance in valence-ionized N2. We show that despite the nuclear motion altering the bond length by only 2%, which leads to tiny changes in the potential barrier, the corresponding change in the ionization time can be as large as 200 attoseconds. This result poses limits to the concept of instantaneous electronic transitions in molecules, which is at the basis of the Franck-Condon principle of molecular spectroscopy.

Shape-Resonance-Enhanced Nuclear-Motion Effects in Molecular Photoionization

1979 ◽  
Vol 43 (14) ◽  
pp. 1005-1008 ◽  
Author(s):  
J. L. Dehmer ◽  
Dan Dill ◽  
Scott Wallace
Keyword(s):  
Shape Resonance ◽  
Nuclear Motion ◽  
Molecular Photoionization

scholarly journals Probing intramolecular vibronic coupling through vibronic-state imaging

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Fan-Fang Kong ◽  
Xiao-Jun Tian ◽  
Yang Zhang ◽  
Yun-Jie Yu ◽  
Shi-Hao Jing ◽  
...  
Keyword(s):  
Single Molecule ◽  
Molecular Spectroscopy ◽  
Transition Density ◽  
Real Space ◽  
Vibronic Coupling ◽  
Vibronic State ◽  
Dipole Orientation ◽  
Transition Dipole ◽  
Franck Condon ◽  
Strong Dynamic

AbstractVibronic coupling is a central issue in molecular spectroscopy. Here we investigate vibronic coupling within a single pentacene molecule in real space by imaging the spatial distribution of single-molecule electroluminescence via highly localized excitation of tunneling electrons in a controlled plasmonic junction. The observed two-spot orientation for certain vibronic-state imaging is found to be evidently different from the purely electronic 0–0 transition, rotated by 90°, which reflects the change in the transition dipole orientation from along the molecular short axis to the long axis. Such a change reveals the occurrence of strong vibronic coupling associated with a large Herzberg–Teller contribution, going beyond the conventional Franck–Condon picture. The emergence of large vibration-induced transition charges oscillating along the long axis is found to originate from the strong dynamic perturbation of the anti-symmetric vibration on those carbon atoms with large transition density populations during electronic transitions.

scholarly journals Complementary vibrational spectroscopy

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Kazuki Hashimoto ◽  
Venkata Ramaiah Badarla ◽  
Akira Kawai ◽  
Takuro Ideguchi
Keyword(s):  
Raman Scattering ◽  
Vibrational Spectroscopy ◽  
Infrared Absorption ◽  
Vibrational Spectra ◽  
Molecular Spectroscopy ◽  
High Spectral Resolution ◽  
Organic Liquids ◽  
Label Free ◽  
Molecular Fingerprint ◽  
Raman Scattering Spectroscopy

Abstract Vibrational spectroscopy, comprised of infrared absorption and Raman scattering spectroscopy, is widely used for label-free optical sensing and imaging in various scientific and industrial fields. The two molecular spectroscopy methods are sensitive to different types of vibrations and provide complementary vibrational spectra, but obtaining complete vibrational information with a single spectroscopic device is challenging due to the large wavelength discrepancy between the two methods. Here, we demonstrate simultaneous infrared absorption and Raman scattering spectroscopy that allows us to measure the complete broadband vibrational spectra in the molecular fingerprint region with a single instrument based on an ultrashort pulsed laser. The system is based on dual-modal Fourier-transform spectroscopy enabled by efficient use of nonlinear optical effects. Our proof-of-concept experiment demonstrates rapid, broadband and high spectral resolution measurements of complementary spectra of organic liquids for precise and accurate molecular analysis.

Application of complex coordinate SCF techniques to a molecular shape resonance: The 2Πg state of N2−

1980 ◽  
Vol 73 (12) ◽  
pp. 6347-6348 ◽  
Author(s):  
T. N. Rescigno ◽  
A. E. Orel ◽  
C. W. McCurdy
Keyword(s):  
Molecular Shape ◽  
Shape Resonance

Ultrafast Nonadiabatic Dynamics. Theoretical Study of Femtosecond Electron Transfer Processes

1998 ◽  
Vol 63 (8) ◽  
pp. 1285-1294 ◽  
Author(s):  
Joshua Jortner ◽  
Mordechai Bixon
Keyword(s):  
Electron Transfer ◽  
Time Scale ◽  
Theoretical Study ◽  
Electronic Coupling ◽  
Nuclear Motion ◽  
Nonadiabatic Dynamics ◽  
Transfer Processes ◽  
Validity Range ◽  
Electron Transfer Processes ◽  
Franck Condon

This paper addresses the conceptual framework of femtosecond nonadiabatic dynamics involving electron transfer processes on the time scale of nuclear motion. Coupling and relaxation of a manifold of doorway states into a weakly correlated Franck-Condon quasicontinuum reflects the extension of the validity range of nonadiabatic dynamics for large values of the electronic coupling, transcendenting the vibrational period of nuclear motion. The theory is applied to ultrafast femtosecond electron transfer processes in solution.

Shape-resonance-induced non-Franck-Condon vibrational intensities in 3 σgphotoionisation of N2

1980 ◽  
Vol 13 (3) ◽  
pp. L105-L108 ◽  
Author(s):  
J B West ◽  
A C Parr ◽  
B E Cole ◽  
D L Ederer ◽  
R Stockbauer ◽  
...  
Keyword(s):  
Shape Resonance ◽  
Franck Condon

scholarly journals The conical shape of DIM lipids promotesMycobacterium tuberculosisinfection of macrophages

2019 ◽  
Vol 116 (51) ◽  
pp. 25649-25658 ◽  
Author(s):  
Jacques Augenstreich ◽  
Evert Haanappel ◽  
Guillaume Ferré ◽  
Georges Czaplicki ◽  
Franck Jolibois ◽  
...  
Keyword(s):  
Molecular Mechanism ◽  
Lipid Bilayers ◽  
Cell Biology ◽  
Biological Response ◽  
Molecular Shape ◽  
General Role ◽  
Ionization Time ◽  
Conical Shape ◽  
Major Virulence Factor ◽  
Molecular Mechanism Of Action

Phthiocerol dimycocerosate (DIM) is a major virulence factor of the pathogenMycobacterium tuberculosis(Mtb). While this lipid promotes the entry ofMtbinto macrophages, which occurs via phagocytosis, its molecular mechanism of action is unknown. Here, we combined biophysical, cell biology, and modeling approaches to reveal the molecular mechanism of DIM action on macrophage membranes leading to the first step ofMtbinfection. Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry showed that DIM molecules are transferred from theMtbenvelope to macrophage membranes during infection. Multiscale molecular modeling and31P-NMR experiments revealed that DIM adopts a conical shape in membranes and aggregates in the stalks formed between 2 opposing lipid bilayers. Infection of macrophages pretreated with lipids of various shapes uncovered a general role for conical lipids in promoting phagocytosis. Taken together, these results reveal how the molecular shape of a mycobacterial lipid can modulate the biological response of macrophages.

DIQUARK FORMATION IN ANGULAR-MOMENTUM-EXCITED BARYONS

2009 ◽  
Vol 24 (10) ◽  
pp. 1987-1994 ◽  
Author(s):  
ANTONIO CARLOS BAPTISTA ANTUNES ◽  
LEILA JORGE ANTUNES
Keyword(s):  
Angular Momentum ◽  
Heavy Quark ◽  
Potential Barrier ◽  
Light Quark ◽  
Heavy Quarks ◽  
Centrifugal Barrier ◽  
Large Angular Momentum

Diquarks, or metastable clusters of two quarks inside baryons, are shown to be produced by angular momentum excitation. In baryons with a light quark and two heavy quarks with large angular momentum (L>2), the centrifugal barrier that appears in the rotation frame of the two heavy quarks prevents the light quark from passing freely between the two heavy quarks. The light quark must tunnelize through this potential barrier, which gives rise to the clusters of a light and a heavy quark.

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