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Iwamoto N, Schwartz CJ, Jochim B, Raju P K, Feizollah P, Napierala JL, Severt T, Tegegn SN, Solomon A, Zhao S, Lam H, Wangjam TN, Kumarappan V, Carnes KD, Ben-Itzhak I, Wells E. Strong-field control of H 3 + production from methanol dications: Selecting between local and extended formation mechanisms. J Chem Phys 2020; 152:054302. [PMID: 32035476 DOI: 10.1063/1.5129946] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Using the CD3OH isotopologue of methanol, the ratio of D2H+ to D3 + formation is manipulated by changing the characteristics of the intense femtosecond laser pulse. Detection of D2H+ indicates a formation process involving two hydrogen atoms from the methyl side of the molecule and a proton from the hydroxyl side, while detection of D3 + indicates local formation involving only the methyl group. Both mechanisms are thought to involve a neutral D2 moiety. An adaptive control strategy that employs image-based feedback to guide the learning algorithm results in an enhancement of the D2H+/D3 + ratio by a factor of approximately two. The optimized pulses have secondary structures 110-210 fs after the main pulse and result in photofragments that have different kinetic energy release distributions than those produced from near transform limited pulses. Systematic changes to the linear chirp and higher order dispersion terms of the laser pulse are compared to the results obtained with the optimized pulse shapes.
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Affiliation(s)
- Naoki Iwamoto
- Department of Physics, Augustana University, Sioux Falls, South Dakota 57197, USA
| | - Charles J Schwartz
- Department of Physics, Augustana University, Sioux Falls, South Dakota 57197, USA
| | - Bethany Jochim
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA
| | - Kanaka Raju P
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA
| | - Peyman Feizollah
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA
| | - J L Napierala
- Department of Physics, Augustana University, Sioux Falls, South Dakota 57197, USA
| | - T Severt
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA
| | - S N Tegegn
- Department of Physics, Augustana University, Sioux Falls, South Dakota 57197, USA
| | - A Solomon
- Department of Physics, Augustana University, Sioux Falls, South Dakota 57197, USA
| | - S Zhao
- Department of Physics, Augustana University, Sioux Falls, South Dakota 57197, USA
| | - Huynh Lam
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA
| | - Tomthin Nganba Wangjam
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA
| | - V Kumarappan
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA
| | - K D Carnes
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA
| | - I Ben-Itzhak
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA
| | - E Wells
- Department of Physics, Augustana University, Sioux Falls, South Dakota 57197, USA
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Madsen CB, Madsen LB, Viftrup SS, Johansson MP, Poulsen TB, Holmegaard L, Kumarappan V, Jørgensen KA, Stapelfeldt H. A combined experimental and theoretical study on realizing and using laser controlled torsion of molecules. J Chem Phys 2009; 130:234310. [DOI: 10.1063/1.3149789] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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Madsen CB, Madsen LB, Viftrup SS, Johansson MP, Poulsen TB, Holmegaard L, Kumarappan V, Jørgensen KA, Stapelfeldt H. Manipulating the torsion of molecules by strong laser pulses. Phys Rev Lett 2009; 102:073007. [PMID: 19257667 DOI: 10.1103/physrevlett.102.073007] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2008] [Indexed: 05/27/2023]
Abstract
We demonstrate that strong laser pulses can induce torsional motion in a molecule consisting of a pair of phenyl rings. A nanosecond laser pulse spatially aligns the carbon-carbon bond axis, connecting the two phenyl rings, allowing a perpendicularly polarized, intense femtosecond pulse to initiate torsional motion accompanied by an overall rotation about the fixed axis. We monitor the induced motion by femtosecond time-resolved Coulomb explosion imaging. Our theoretical analysis accounts for and generalizes the experimental findings.
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Affiliation(s)
- C B Madsen
- Lundbeck Foundation Theoretical Center for Quantum System Research, Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark
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Milchberg HM, Kim KY, Kumarappan V, Layer BD, Sheng H. Clustered gases as a medium for efficient plasma waveguide generation. Philos Trans A Math Phys Eng Sci 2006; 364:647-61. [PMID: 16483955 DOI: 10.1098/rsta.2005.1729] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Clustered gas jets are shown to be an efficient means for plasma waveguide generation, for both femtosecond and picosecond generation pulses. These waveguides enable significantly lower on-axis plasma density (less than 10(18) cm(-3)) than in conventional hydrodynamic plasma waveguides generated in unclustered gases. Using femtosecond pump pulses, self-guided propagation and strong absorption (more than 70%) are used to produce long centimetre scale channels in an argon cluster jet, and a subsequent intense pulse is coupled into the guide with 50% efficiency and guided at above 10(17)W cm(-2) intensity over 40 Rayleigh lengths. We also demonstrate efficient generation of waveguides using 100 ps axicon-generated Bessel-beam pump pulses. Despite the expected sub-picosecond cluster disassembly time, we observe long pulse absorption efficiencies up to a maximum of 35%. Simulations show that in the far leading edge of the long laser pulse, the volume of heated clusters evolves to a locally uniform and cool plasma already near ionization saturation, which is then efficiently heated by the remainder of the pulse.
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Affiliation(s)
- H M Milchberg
- University of Maryland Institute for Physical Science and Technology College Park, MD 20742, USA
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Sheng H, Kim KY, Kumarappan V, Layer BD, Milchberg HM. Plasma waveguides efficiently generated by Bessel beams in elongated cluster gas jets. Phys Rev E Stat Nonlin Soft Matter Phys 2005; 72:036411. [PMID: 16241583 DOI: 10.1103/physreve.72.036411] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2005] [Indexed: 05/05/2023]
Abstract
We demonstrate the efficient generation of plasma waveguides in elongated cluster gas jets using 100 ps axicon-generated Bessel beam pump pulses. The plasma waveguide space and time evolution is measured using picosecond interferometry. Small radius waveguides with central densities as low as approximately 10(18) cm(-3) can be generated with this technique. Despite the expected subpicosecond cluster disassembly time, we observe long pulse absorption efficiencies that can be more than a factor of 10 greater than in unclustered gas targets of the same volume average atomic density. The maximum long pulse absorption observed in cluster jets under our range of conditions was 35%. The explanation for the enhanced absorption is that in the far-leading edge of the laser pulse, the volume of heated clusters evolves to a locally uniform and cool plasma already near ionization saturation, which is then heated by the remainder of the pulse. From this perspective, the use of clustered gases is equivalent to a supercharged preionization scheme for long duration laser pulses.
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Affiliation(s)
- H Sheng
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
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Kumarappan V, Kim KY, Milchberg HM. Guiding of intense laser pulses in plasma waveguides produced from efficient, femtosecond end-pumped heating of clustered gases. Phys Rev Lett 2005; 94:205004. [PMID: 16090259 DOI: 10.1103/physrevlett.94.205004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2004] [Indexed: 05/03/2023]
Abstract
We demonstrate intense pulse guiding in efficient femtosecond end-pumped waveguides generated in clustered gases. This novel scheme provides a route to significantly lower on-axis plasma density (< 10(18) cm(-3)) more than is feasible in conventional hydrodynamic plasma waveguides. Self-focused propagation and strong absorption of intense femtosecond laser pulses are used to produce long centimeter scale channels in an argon cluster jet, and a subsequent pulse is guided with 3 x 10(17) W cm(-2) intensity and approximately 50% coupling efficiency. Preliminary results with hydrogen clusters also show guiding.
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Affiliation(s)
- V Kumarappan
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
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Kumarappan V, Krishnamurthy M, Mathur D. Asymmetric high-energy ion emission from argon clusters in intense laser fields. Phys Rev Lett 2001; 87:085005. [PMID: 11497952 DOI: 10.1103/physrevlett.87.085005] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2001] [Revised: 04/27/2001] [Indexed: 05/23/2023]
Abstract
Clusters of 2x10(3) to 4x10(4) Ar atoms are Coulomb exploded in intense (up to 8x10(15) W cm(-2)) laser fields. The dependence of multiply charged argon ion energies on the polarization state of light is probed. A directional asymmetry in the ion-explosion energies is observed for the highest charge states. The ion-energy distribution consists of a low-energy isotropic component, and a high-energy anisotropic one. The results are discussed in terms of an asymmetric Coulomb-explosion scenario.
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Affiliation(s)
- V Kumarappan
- Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India
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