scholarly journals Electronic and vibrational relaxation dynamics of NH3 Rydberg states probed by vacuum-ultraviolet time-resolved photoelectron imaging

2019 ◽  
Vol 151 (10) ◽  
pp. 104306 ◽  
Author(s):  
Vít Svoboda ◽  
Chuncheng Wang ◽  
Max D. J. Waters ◽  
Hans Jakob Wörner
2019 ◽  
Author(s):  
Ole Hüter ◽  
Niklas Helle ◽  
Friedrich Temps

<div>The radiationless decay dynamics of the S1 (nπ*) state and the 3p and 3d Rydberg states of cyclohexanone are investigated using femtosecond time-resolved time-of- flight mass spectrometry and photoelectron imaging spectroscopy. After two-photon excitation of the 3p and 3d states, an ultrafast population transfer to the 3s state is observed within < 120 fs. We ascribe this behavior to strong vibronic interactions of the excited Rydberg states with the <sup>1</sup>ππ* valence state that enable an ultrafast population transfer via an avoided crossing and the subsequent passage of a conical intersection between the respective electronic states. Eventually, the 3s state deactivates by internal conversion to the S<sub>1</sub> (nπ*) state, which in turn is found to be long-lived with a decay time of ~ 300 - 800 ps.</div>


2019 ◽  
Author(s):  
Ole Hüter ◽  
Niklas Helle ◽  
Friedrich Temps

<div>The radiationless decay dynamics of the S1 (nπ*) state and the 3p and 3d Rydberg states of cyclohexanone are investigated using femtosecond time-resolved time-of- flight mass spectrometry and photoelectron imaging spectroscopy. After two-photon excitation of the 3p and 3d states, an ultrafast population transfer to the 3s state is observed within < 120 fs. We ascribe this behavior to strong vibronic interactions of the excited Rydberg states with the <sup>1</sup>ππ* valence state that enable an ultrafast population transfer via an avoided crossing and the subsequent passage of a conical intersection between the respective electronic states. Eventually, the 3s state deactivates by internal conversion to the S<sub>1</sub> (nπ*) state, which in turn is found to be long-lived with a decay time of ~ 300 - 800 ps.</div>


2018 ◽  
Vol 148 (14) ◽  
pp. 144311 ◽  
Author(s):  
Fengzi Ling ◽  
Shuai Li ◽  
Jie Wei ◽  
Kai Liu ◽  
Yanmei Wang ◽  
...  

1999 ◽  
Vol 19 (1-4) ◽  
pp. 75-78 ◽  
Author(s):  
Takakazu Nakabayashi ◽  
Hiromi Okamoto ◽  
Mitsuo Tasumi

Vibrational relaxation dynamics of trans-stilbene in the S1 state immediately after photoexcitation is studied by picosecond time-resolved anti-Stokes Raman spectroscopy with several pump and probe wavelengths. Pump-wavelength dependence of the anti- Stokes spectrum indicates that, when pump photons with high excess energy (≈5200cm-1) are used, the anti-Stokes Raman bands at 0 ps delay time arise from vibrationally excited transients with excess vibrational energy not thermally distributed in the molecule. Probe-wavelength dependence suggests that the vibrationally excited transients at 0 ps are mostly on the lowest excited vibrational levels, as far as the olefinic C═C stretching and the C–Ph stretching modes are concerned. The vibrational relaxation process of S1trans-stilbene is discussed on the basis of the observed results.


2016 ◽  
Vol 194 ◽  
pp. 185-208 ◽  
Author(s):  
Magdalena M. Zawadzki ◽  
Marco Candelaresi ◽  
Lisa Saalbach ◽  
Stuart W. Crane ◽  
Martin J. Paterson ◽  
...  

We present results from a recent time-resolved photoelectron imaging (TRPEI) study investigating the non-adiabatic relaxation dynamics of N,N-dimethylaniline (N,N-DMA) and 3,5-dimethylaniline (3,5-DMA) following excitation at 240 nm. Analysis of the experimental data is supported by ab initio coupled-cluster calculations evaluating excited state energies and the evolution of several excited state physical properties as a function of N–H/N–CH3 bond extension – a critical reaction coordinate. The use of site-selective methylation brings considerable new insight to the existing body of literature concerning photochemical dynamics in the related system aniline at similar excitation wavelengths. The present work also builds on our own previous investigations in the same species at 250 nm. The TRPEI method provides highly differential energy- and angle-resolved data and, in particular, the temporal evolution of the photoelectron angular distributions afforded by the imaging approach offers much of the new dynamical information. In particular, we see no clear evidence of the second excited 2ππ* state non-adiabatically coupling to the lower-lying S1(ππ*) state or the mixed Rydberg/valence S2(3s/πσ*) state. This, in turn, potentially raises some unresolved questions about the overall nature of the dynamics operating in these systems, especially in regard to the 2ππ* state's ultimate fate. More generally, the findings for the aromatic systems N,N-DMA and 3,5-DMA, taken along with our recent TRPEI results for several aliphatic amine species, highlight interesting questions about the nature of electronic character evolution in mixed Rydberg-valence states as a function of certain key bond extensions and the extent of system conjugation. We begin exploring these ideas computationally for a systematically varied series of tertiary amines.


2004 ◽  
Vol 121 (8) ◽  
pp. 3515-3526 ◽  
Author(s):  
Arthur E. Bragg ◽  
Jan R. R. Verlet ◽  
Aster Kammrath ◽  
Daniel M. Neumark

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