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Title: Stark-assisted population control of coherent CS2 4f and 5pRydberg wave packets studied by femtosecond time-resolved photoelectronspectroscopy

Abstract

No abstract prepared.

Authors:
; ; ;
Publication Date:
Research Org.:
COLLABORATION - University of California,Berkeley
OSTI Identifier:
932558
Report Number(s):
LBNL-63486
R&D Project: 400101; TRN: US0803538
DOE Contract Number:
DE-AC02-05CH11231
Resource Type:
Journal Article
Resource Relation:
Journal Name: American Institute of Physics; Journal Volume: 127; Related Information: Journal Publication Date: 09/28/2007
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; PHOTOELECTRON SPECTROSCOPY; WAVE PACKETS; RYDBERG STATES

Citation Formats

Knappemberger, Kenneth L.Jr., Lerch, Eliza-Beth W., Wen, Patrick, and Leone, Stephen R. Stark-assisted population control of coherent CS2 4f and 5pRydberg wave packets studied by femtosecond time-resolved photoelectronspectroscopy. United States: N. p., 2007. Web.
Knappemberger, Kenneth L.Jr., Lerch, Eliza-Beth W., Wen, Patrick, & Leone, Stephen R. Stark-assisted population control of coherent CS2 4f and 5pRydberg wave packets studied by femtosecond time-resolved photoelectronspectroscopy. United States.
Knappemberger, Kenneth L.Jr., Lerch, Eliza-Beth W., Wen, Patrick, and Leone, Stephen R. Tue . "Stark-assisted population control of coherent CS2 4f and 5pRydberg wave packets studied by femtosecond time-resolved photoelectronspectroscopy". United States. doi:.
@article{osti_932558,
title = {Stark-assisted population control of coherent CS2 4f and 5pRydberg wave packets studied by femtosecond time-resolved photoelectronspectroscopy},
author = {Knappemberger, Kenneth L.Jr. and Lerch, Eliza-Beth W. and Wen, Patrick and Leone, Stephen R.},
abstractNote = {No abstract prepared.},
doi = {},
journal = {American Institute of Physics},
number = ,
volume = 127,
place = {United States},
year = {Tue May 01 00:00:00 EDT 2007},
month = {Tue May 01 00:00:00 EDT 2007}
}
  • No abstract prepared.
  • Explicitly time-dependent density functional theory (TDDFT) is a formally exact theory, which can treat very large systems. However, in practice it is used almost exclusively in the adiabatic approximation and with standard ground state functionals. Therefore, if combined with coherent control theory, it is not clear which control tasks can be achieved reliably, and how this depends on the functionals. In this paper, we continue earlier work in order to establish rules that answer these questions. Specifically, we look at the creation of wave packets by ultrashort laser pulses that contain several excited states. We find that (i) adiabatic TDDFTmore » only works if the system is not driven too far from the ground state, (ii) the permanent dipole moments involved should not differ too much, and (iii) these results are independent of the functional used. Additionally, we find an artifact that produces fluence-dependent excitation energies.« less
  • A two-color (3+1{sup '}) pump-probe scheme is used to create Rydberg wave packets in krypton atoms. The ac-Stark shift, caused by the high intensity pump pulse, allows access to states with principal quantum numbers n=5-10 over a broad energy range. States shifted by as much as 3000 cm{sup -1} during the pump pulse are coherently excited, resulting in wave-packet superpositions of field free states. By resolving the kinetic energy of the photoelectrons produced in the ionization probe step, numerous quantum beats are resolved and assigned. In addition, the energies of four previously unmeasured g states are determined.
  • Nonperturbative quantum control schemes in the intermediate field strength (nonionizing) regime are investigated. We restrict the matter-field interaction to the nonresonant dynamic Stark effect (NRDSE) as induced by infrared laser fields, which we argue is a new and general tool for quantum control of atomic and molecular dynamics. For the case of Raman coupled matter states, an effective Hamiltionian may be constructed, and quantum control via NRDSE may be thought of as reversibly modifying the effective Hamiltonian during system propagation, thus leading to control over dynamic processes. As an illustration, the creation of field-free 'switched' wave packets through the adiabaticmore » turn on and sudden turn off of the NRDSE is considered and experimentally demonstrated. Wave packets generated through the switched NRDSE interaction may be very different in form and content than wave packets generated via resonant transitions with Gaussian optical pulses. In order to provide an example, we discuss the specific case of rotational wave packet dynamics where the NRDSE manifests itself as molecular axis alignment. This technique is applied to the creation of field-free molecular axis alignment using an intense switched 1.064 {mu}m laser pulse. This switched laser pulse was generated via a plasma shuttering technique, giving a pulse with a rise time of 150 ps and a fall time of 170 fs. The temporal evolution of the molecular axis alignment is probed via the optical Kerr effect. Field-free alignment via the switched NRDSE is demonstrated for both linear (CO{sub 2}, CS{sub 2}) and symmetric top (1,2-propadiene) polyatomic molecules.« less
  • Ultrafast processes in photoexcited N-salicylideneaniline have been investigated with femtosecond time-resolved resonance-enhanced multiphoton ionization spectroscopy. The ion signals via the S{sub 1}(n,{pi}*) state of the enol form as well as the proton-transferred cis-keto form emerge within a few hundred femtoseconds after photoexcitation to the first S{sub 1}({pi},{pi}*) state of the enol form. This reveals that two ultrafast processes, excited-state intramolecular proton transfer (ESIPT) reaction and an internal conversion (IC) to the S{sub 1}(n,{pi}*) state, occur on a time scale less than a few hundred femtoseconds from the S{sub 1}({pi},{pi}*) state of the enol form. The rise time of the transientmore » corresponding to the production of the proton-transferred cis-keto form is within 750 fs when near the red edge of the absorption is excited, indicating that the ESIPT reaction occurs within 750 fs. The decay time of the S{sub 1}({pi},{pi}*) state of the cis-keto form is 8.9 ps by exciting the enol form at 370 nm, but it dramatically decreases to be 1.5-1.6 ps for the excitation at 365-320 nm. The decrease in the decay time has been attributed to the opening of an efficient nonradiative channel; an IC from S{sub 1}({pi},{pi}*) to S{sub 1}(n,{pi}*) of the cis-keto form promotes the production of the trans-keto form as the final photochromic products. The two IC processes may provide opposite effect on the quantum yield of photochromic products: IC in the enol form may substantially reduce the quantum yield, but IC in the cis-keto form increase it.« less