The Experts below are selected from a list of 216 Experts worldwide ranked by ideXlab platform
John M Doyle - One of the best experts on this subject based on the ideXlab platform.
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establishing a highly closed cycling transition in a Polyatomic Molecule
arXiv: Atomic Physics, 2020Co-Authors: Louis Baum, Benjamin L Augenbraun, Nathaniel B Vilas, Christian Hallas, Shivam Rava, Debayan Mitra, John M DoyleAbstract:We study optical cycling in the polar free radical calcium monohydroxide (CaOH) and establish an experimental path towards scattering >$10^4$ photons. We report vibrational branching ratio measurements with accuracy at the $\sim$$5 \times 10^{-4}$ level and observe weak symmetry-forbidden decays to bending modes with non-zero vibrational angular momentum. Quantitative theory is developed to explain these observations and predict additional decay pathways. Additionally, we perform high-resolution spectroscopy of the $\widetilde{\text{X}}\,^2\Sigma^+(12^00)$ and $\widetilde{\text{X}}\,^2\Sigma^+(12^20)$ hybrid vibrational states of CaOH. These advances establish a path towards radiative slowing, 3D magneto-optical trapping, and sub-Doppler cooling of CaOH.
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sisyphus laser cooling of a Polyatomic Molecule
Physical Review Letters, 2017Co-Authors: Ivan Kozyryev, Louis Baum, Kyle Matsuda, Benjamin L Augenbraun, Loic Anderegg, Alexander Sedlack, John M DoyleAbstract:: We perform magnetically assisted Sisyphus laser cooling of the triatomic free radical strontium monohydroxide (SrOH). This is achieved with principal optical cycling in the rotationally closed P(N^{''}=1) branch of either the X[over ˜]^{2}Σ^{+}(000)↔A[over ˜]^{2}Π_{1/2}(000) or the X[over ˜]^{2}Σ^{+}(000)↔B[over ˜]^{2}Σ^{+}(000) vibronic transitions. Molecules lost into the excited vibrational states during the cooling process are repumped back through the B[over ˜](000) state for both the (100) level of the Sr-O stretching mode and the (02^{0}0) level of the bending mode. The transverse temperature of a SrOH molecular beam is reduced in one dimension by 2 orders of magnitude to ∼750 μK. This approach opens a path towards creating a variety of ultracold Polyatomic Molecules by means of direct laser cooling.
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radiation pressure force from optical cycling on a Polyatomic Molecule
Journal of Physics B, 2016Co-Authors: Ivan Kozyryev, Louis Baum, Kyle Matsuda, John M Doyle, Boerge HemmerlingAbstract:We demonstrate multiple photon cycling and radiative force deflection on the triatomic free radical strontium monohydroxide (SrOH). Optical cycling is achieved on SrOH in a cryogenic buffer-gas beam by employing the rotationally closed branch of the vibronic transition . A single repumping laser excites the Sr–O stretching vibrational mode, and photon cycling of the Molecule deflects the SrOH beam by an angle of via scattering of ~100 photons per Molecule. This approach can be used for direct laser cooling of SrOH and more complex, isoelectronic species.
Y Suzuki - One of the best experts on this subject based on the ideXlab platform.
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time resolved photoelectron imaging of ultrafast s2 s1 internal conversion through conical intersection in pyrazine
Journal of Chemical Physics, 2010Co-Authors: Y Suzuki, Takao Fuji, Takuya Horio, Toshinori SuzukiAbstract:A nonadiabatic electronic transition through a conical intersection was studied by pump-probe photoelectron imaging spectroscopy with a 22 fs time resolution in the benchmark Polyatomic Molecule of pyrazine and deuterated pyrazine. The lifetimes of the S2 state of pyrazine and deuterated pyrazine were determined to be 22±3 fs by the global fitting of the time-energy maps of photoelectron kinetic energy (PKE) distributions. The lifetime of S3 was determined to be 40–43 fs. Two-dimensional maps of photoelectron distributions were obtained for time (t) and PKE, and individual PKE distributions upon ionization from S2 and S1 were extracted. Quantum beat with an approximately 50 fs period was observed after the S2→S1 internal conversion, which was attributed to the totally symmetric vibration ν6a in S1.
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theory of time resolved photoelectron imaging nonperturbative calculation for an internally converting Polyatomic Molecule
Physical Review Letters, 2002Co-Authors: Y Suzuki, Mauro Stener, Tamar SeidemanAbstract:: We present the first calculation of time-resolved photoelectron angular distributions for a Polyatomic system. Our method takes rotations into exact account, treats the laser field nonperturbatively, and computes the electronic dynamics from first principles. Our results point to the information content of time-resolved photoelectron imaging observables and illustrate the role played by the field intensity.
Jean-pierre Gauyacq - One of the best experts on this subject based on the ideXlab platform.
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Model study of vibrational excitation in electron−Polyatomic Molecule collisions
Journal of Physics B, 1990Co-Authors: Jean-pierre GauyacqAbstract:The effective range approximation, which has been limited to the treatment of electron-diatomic Molecule interactions, is generalized to the case of electron-Polyatomic Molecule collisions. A model study of the vibrational excitation process is presented with the aim of recognizing features specific to the Polyatomic targets. The model target Molecule is modelled by a two vibrational mode Molecule, one of the vibrational frequencies being very small to mimic a quasicontinuum of vibrational levels. It is found that the vibrational modes of the Molecule cannot be treated independently, and that a resonance created by the motion along one coordinate can induce a vibrational excitation along another coordinate. This effect is analysed by looking at the time delay and time dependence of the vibrational excitation process. A significant production of low energy electrons is also observed in the resonance region, thus yielding an interpretation of the 'unspecific' vibrational excitation observed by Allan (1984,1988,1989) in large Polyatomics.
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model study of vibrational excitation in electron Polyatomic Molecule collisions
Journal of Physics B, 1990Co-Authors: Jean-pierre GauyacqAbstract:The effective range approximation, which has been limited to the treatment of electron-diatomic Molecule interactions, is generalized to the case of electron-Polyatomic Molecule collisions. A model study of the vibrational excitation process is presented with the aim of recognizing features specific to the Polyatomic targets. The model target Molecule is modelled by a two vibrational mode Molecule, one of the vibrational frequencies being very small to mimic a quasicontinuum of vibrational levels. It is found that the vibrational modes of the Molecule cannot be treated independently, and that a resonance created by the motion along one coordinate can induce a vibrational excitation along another coordinate. This effect is analysed by looking at the time delay and time dependence of the vibrational excitation process. A significant production of low energy electrons is also observed in the resonance region, thus yielding an interpretation of the 'unspecific' vibrational excitation observed by Allan (1984,1988,1989) in large Polyatomics.
Tamar Seideman - One of the best experts on this subject based on the ideXlab platform.
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theory of time resolved photoelectron imaging nonperturbative calculation for an internally converting Polyatomic Molecule
Physical Review Letters, 2002Co-Authors: Y Suzuki, Mauro Stener, Tamar SeidemanAbstract:: We present the first calculation of time-resolved photoelectron angular distributions for a Polyatomic system. Our method takes rotations into exact account, treats the laser field nonperturbatively, and computes the electronic dynamics from first principles. Our results point to the information content of time-resolved photoelectron imaging observables and illustrate the role played by the field intensity.
Robert J Huber - One of the best experts on this subject based on the ideXlab platform.
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nuclear quadrupole quantum beat spectroscopy in the electronic ground state of a Polyatomic Molecule by an ir uv double resonance method
Chemical Physics Letters, 1995Co-Authors: Robert T Carter, Th Walther, H Bitto, Robert J HuberAbstract:The feasibility of determining nuclear quadrupole hyperfine splittings in the ground electronic state of a Polyatomic Molecule using a double resonance quantum beat method has been demonstrated. Pyrimidine Molecules were coherently excited into single rotational states of the S0 201 (13a1) vibrational level. The resulting hyperfine level coherences were then probed, after a variable time delay, by excitation to the S1 O0 level with subsequent fluorescence detection. Analysis showed that the quadrupole structure in the 201 (13a1) level is similar to that previously measured in the vibrational ground state. Applications of this method and possible experimental extensions are discussed.
