Controlling the Excited-State Dynamics of Nuclear Spin Isomers Using the Dynamic Stark Effect

2016 ◽  
Vol 120 (27) ◽  
pp. 4907-4914 ◽  
Author(s):  
Maria Waldl ◽  
Markus Oppel ◽  
Leticia González
Keyword(s):  
Excited State ◽  
Nuclear Spin ◽  
Stark Effect ◽  
Excited State Dynamics ◽  
Dynamic Stark Effect ◽  
Spin Isomers

Discrimination of nuclear spin isomers exploiting the excited state dynamics of a quinodimethane derivative

2014 ◽  
Vol 141 (16) ◽  
pp. 164323 ◽  
Author(s):  
Rana Obaid ◽  
Daniel Kinzel ◽  
Markus Oppel ◽  
Leticia González
Keyword(s):  
Excited State ◽  
Nuclear Spin ◽  
Excited State Dynamics ◽  
Spin Isomers

Interference spectra in a two-level atom

1990 ◽  
Vol 68 (12) ◽  
pp. 1389-1395 ◽  
Author(s):  
Constantine Mavroyannis
Keyword(s):  
Excited State ◽  
High Intensity ◽  
Laser Field ◽  
Stark Effect ◽  
Ground States ◽  
Spectral Functions ◽  
Laser Photon ◽  
Level Atom ◽  
Dynamic Stark Effect ◽  
Two Peaks

We have considered the interference spectra arising from the competition between a spontaneous process and one induced by a laser field in a two-level atom. Expressions for the spectral functions have been derived describing the spectra of the excited and ground states of the atom in the low- and high-intensity limit of the laser field. For the excited-state spectra in the low-intensity limit, the frequency profiles of the two peaks, which arise from the spontaneous and the induced processes, cancel each other out completely near the center of the line, while for the ground state the induced process dominates. For finite values of the detuning, the spectra of the excited state consist of two peaks, which have positive and negative frequency profiles, respectively. The computed spectra have been graphically presented and discussed. In the high-intensity limit, the dynamic Stark effect dominates the spectra of the excited and ground states of the atom. Expressions for the correlation functions have been derived that describe the emission or the absorption of a laser photon at two different times. The derived expressions for the corresponding delay functions in the low- and high-intensity limits have been found to be identical to those recently proposed in the literature. The laser field has been treated as a classical as well as a quantized entity.

Two-photon interference spectra induced by a bichromatic field in the excited state of a single three-level ion

1992 ◽  
Vol 70 (1) ◽  
pp. 1-23 ◽  
Author(s):  
Constantine Mavroyannis
Keyword(s):  
Excited State ◽  
Ground State ◽  
Correlation Functions ◽  
Stark Effect ◽  
Stimulated Emission ◽  
Laser Fields ◽  
Two Photon ◽  
Dynamic Stark Effect ◽  
Two Peaks ◽  
Photon Resonance

We consider the interference spectra arising from the competition between a spontaneous process and two processes induced by two laser fields, which are coupled with a three-level atom in the "Λ" configuration. In the low-intensity limit of both laser fields and on two-photon resonance, the frequency profiles of the two peaks, which arise from the spontaneous and induced processes, cancel each other out completely at the center of the line for zero detuning and at the finite values of the detuning as well. At high intensities of the laser fields and on two-photon resonance, the dynamic Stark effect dominates the spectra of the excited state of the atom. Expressions for the interference spectra and correlation functions are derived, which describe the physical process of the absorption of a laser photon at two different times by the ground state of the atom. Interference spectra and correlation functions are calculated for the two-photon off-resonance and for the proces of the absorption of a photon by the ground state of the atom. In this case, the intensities of the frequency dips take negative values indicating that stimulated emission prevails for certain values of the detunings. Using values for the parameters involved close to those for Ba+, the computed two-photon resonance and off-resonance spectra are graphically presented and discussed.

Excited-State Dynamics in the RNA Nucleotide Uridine 5’-Monophosphate Investigated by Femtosecond Broadband Transient Absorption Spectroscopy

2019 ◽  
Author(s):  
Matthew M. Brister ◽  
Carlos Crespo-Hernández
Keyword(s):  
Excited State ◽  
Excited States ◽  
Ground State ◽  
Transient Absorption ◽  
Electronic Energy ◽  
Transient Absorption Spectroscopy ◽  
Electronic Relaxation ◽  
Vibrationally Excited ◽  
Excited State Dynamics ◽  
Π State

<p></p><p> Damage to RNA from ultraviolet radiation induce chemical modifications to the nucleobases. Unraveling the excited states involved in these reactions is essential, but investigations aimed at understanding the electronic-energy relaxation pathways of the RNA nucleotide uridine 5’-monophosphate (UMP) have not received enough attention. In this Letter, the excited-state dynamics of UMP is investigated in aqueous solution. Excitation at 267 nm results in a trifurcation event that leads to the simultaneous population of the vibrationally-excited ground state, a longlived <sup>1</sup>n<sub>O</sub>π* state, and a receiver triplet state within 200 fs. The receiver state internally convert to the long-lived <sup>3</sup>ππ* state in an ultrafast time scale. The results elucidate the electronic relaxation pathways and clarify earlier transient absorption experiments performed for uracil derivatives in solution. This mechanistic information is important because long-lived nπ* and ππ* excited states of both singlet and triplet multiplicities are thought to lead to the formation of harmful photoproducts.</p><p></p>

Modulation of Excited State Dynamics in Lead Halide Perovskite Films with Electrical Bias

2019 ◽  
Author(s):  
Gergely Samu ◽  
R.A. Scheidt ◽  
A. Balog ◽  
C. Janáky ◽  
P.V. Kamat
Keyword(s):  
Excited State ◽  
Excited State Dynamics ◽  
Halide Perovskite ◽  
Electrical Bias ◽  
Lead Halide
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