The Experts below are selected from a list of 213 Experts worldwide ranked by ideXlab platform
J. N. Murrell - One of the best experts on this subject based on the ideXlab platform.
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Analytical Functions for the Potential Energy Surfaces of Small Polyatomic Molecules
Israel Journal of Chemistry, 2013Co-Authors: J. N. MurrellAbstract:A review is given of a recently developed method of constructing analytical functions to represent the potential energy surfaces of small Polyatomic Molecules.
Gerhard Rempe - One of the best experts on this subject based on the ideXlab platform.
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Sisyphus cooling of electrically trapped Polyatomic Molecules
Nature, 2012Co-Authors: Martin Zeppenfeld, Barbara G. U. Englert, Rosa Glöckner, Alexander Prehn, Manuel Mielenz, Christian Sommer, Laurens D. Van Buuren, Michael Motsch, Gerhard RempeAbstract:A general method of cooling Polyatomic Molecules to ultracold temperatures is reported; the optoelectrical cooling technique removes kinetic energy via a Sisyphus effect, effectively causing the Molecules to continually ‘climb’ a hill of potential energy. Ultracold polar Molecules are of interest for various fundamental studies, including quantum-information science, ultracold chemistry and physics beyond the standard model. However, a general method for cooling Polyatomic Molecules to ultracold temperatures has been lacking. This paper demonstrates an optoelectrical cooling technique that can reduce the temperature of about a million methyl fluoride (CH3F) Molecules by a factor of more than ten. The scheme removes kinetic energy by means of a 'Sisyphus effect' that causes the Molecules to continually 'climb' a hill of potential energy. In contrast to other cooling mechanisms, it proceeds in a trap, cools in all three dimensions and should work for a large variety of polar Molecules. The chip-like trap and guide architecture used in this work are well suited to use in quantum-information processing with cold and ultracold Molecules. Polar Molecules have a rich internal structure and long-range dipole–dipole interactions, making them useful for quantum-controlled applications and fundamental investigations. Their potential fully unfolds at ultracold temperatures, where various effects are predicted in many-body physics1,2, quantum information science3,4, ultracold chemistry5,6 and physics beyond the standard model7,8. Whereas a wide range of methods to produce cold molecular ensembles have been developed9,10,11,12,13, the cooling of Polyatomic Molecules (that is, with three or more atoms) to ultracold temperatures has seemed intractable. Here we report the experimental realization of optoelectrical cooling14, a recently proposed cooling and accumulation method for polar Molecules. Its key attribute is the removal of a large fraction of a molecule’s kinetic energy in each cycle of the cooling sequence via a Sisyphus effect, allowing cooling with only a few repetitions of the dissipative decay process. We demonstrate the potential of optoelectrical cooling by reducing the temperature of about one million CH3F Molecules by a factor of 13.5, with the phase-space density increased by a factor of 29 (or a factor of 70 discounting trap losses). In contrast to other cooling mechanisms, our scheme proceeds in a trap, cools in all three dimensions and should work for a large variety of polar Molecules. With no fundamental temperature limit anticipated down to the photon-recoil temperature in the nanokelvin range, we expect our method to be able to produce ultracold Polyatomic Molecules. The low temperatures, large molecule numbers and long trapping times of up to 27 seconds should allow an interaction-dominated regime to be attained, enabling collision studies and investigation of evaporative cooling towards a Bose–Einstein condensate of Polyatomic Molecules.
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Sisyphus cooling of electrically trapped Polyatomic Molecules
Nature, 2012Co-Authors: Martin Zeppenfeld, Barbara G. U. Englert, Rosa Glöckner, Alexander Prehn, Manuel Mielenz, Christian Sommer, Michael Motsch, Laurens D. Van Buuren, Gerhard RempeAbstract:Polar Molecules have a rich internal structure and long-range dipole-dipole interactions, making them useful for quantum-controlled applications and fundamental investigations. Their potential fully unfolds at ultracold temperatures, where various effects are predicted in many-body physics, quantum information science, ultracold chemistry and physics beyond the standard model. Whereas a wide range of methods to produce cold molecular ensembles have been developed, the cooling of Polyatomic Molecules (that is, with three or more atoms) to ultracold temperatures has seemed intractable. Here we report the experimental realization of optoelectrical cooling, a recently proposed cooling and accumulation method for polar Molecules. Its key attribute is the removal of a large fraction of a molecule's kinetic energy in each cycle of the cooling sequence via a Sisyphus effect, allowing cooling with only a few repetitions of the dissipative decay process. We demonstrate the potential of optoelectrical cooling by reducing the temperature of about one million CH(3)F Molecules by a factor of 13.5, with the phase-space density increased by a factor of 29 (or a factor of 70 discounting trap losses). In contrast to other cooling mechanisms, our scheme proceeds in a trap, cools in all three dimensions and should work for a large variety of polar Molecules. With no fundamental temperature limit anticipated down to the photon-recoil temperature in the nanokelvin range, we expect our method to be able to produce ultracold Polyatomic Molecules. The low temperatures, large molecule numbers and long trapping times of up to 27 seconds should allow an interaction-dominated regime to be attained, enabling collision studies and investigation of evaporative cooling towards a Bose-Einstein condensate of Polyatomic Molecules.
Pratt St - One of the best experts on this subject based on the ideXlab platform.
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Vibrational autoionization in Polyatomic Molecules.
Annual Review of Physical Chemistry, 2005Co-Authors: Pratt StAbstract:: The vibrationally autoionizing Rydberg states of small Polyatomic Molecules provide a fascinating laboratory in which to study fundamental nonadiabatic processes. In this review, recent results on the vibrational mode dependence of vibrational autoionization are discussed. In general, autoionization rates depend strongly on the character of the normal mode driving the process and on the electronic character of the Rydberg electron. Although quantitative calculations based on multichannel quantum defect theory are available for some Polyatomic Molecules, including H3, only qualitative information exists for most Molecules. This review shows how qualitative information, such as Walsh diagrams along different normal coordinates of the molecule, can provide insight into the vibrational autoionization rates.
Dejan B. Milošević - One of the best experts on this subject based on the ideXlab platform.
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Strong-field-approximation theory of high-order harmonic generation by Polyatomic Molecules
Physical Review A, 2016Co-Authors: S. Odžak, E. Hasović, Dejan B. MiloševićAbstract:A theory of high-order harmonic generation by arbitrary Polyatomic Molecules is introduced. A Polyatomic molecule is modeled by an $(N+1)$-particle system, which consists of $N$ heavy atomic (ionic) centers and an electron. After the separation of the center-of-mass coordinate, the dynamics of this system is reduced to the relative electronic and nuclear coordinates. Various versions (with or without the dressing of the initial and/or final molecular state) of the molecular strong-field approximation are introduced. For neutral Polyatomic Molecules the derived expression for the $T$-matrix element takes a simple form. The interference minima in the harmonic spectrum are explained as a multiple-slit type of interference. This is illustrated by numerical examples for the ozone (${\mathrm{O}}_{3}$) and carbon dioxide (${\mathrm{CO}}_{2}$) Molecules.
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Strong-field approximation for above-threshold ionization of Polyatomic Molecules
Physical Review A, 2012Co-Authors: E. Hasović, Dejan B. MiloševićAbstract:We consider above-threshold ionization of Polyatomic Molecules by a strong laser field within the molecular strong-field approximation (MSFA). A Polyatomic molecule is modeled by an $(N+1)$-particle system, which consists of $N$ heavy atomic (ionic) centers and an electron. After the separation of the center-of-mass coordinate, the dynamics of this system is reduced to the relative electronic and nuclear coordinates. Two forms of the MSFA, one with the field-free and the other with the field-dressed initial molecular bound state, are derived. For neutral Polyatomic Molecules the ionization amplitude takes a simple form which allows interpretation as a multiple-slit-type interference. This is illustrated by a numerical example for the ozone molecule.
Martin Zeppenfeld - One of the best experts on this subject based on the ideXlab platform.
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Sisyphus cooling of electrically trapped Polyatomic Molecules
Nature, 2012Co-Authors: Martin Zeppenfeld, Barbara G. U. Englert, Rosa Glöckner, Alexander Prehn, Manuel Mielenz, Christian Sommer, Laurens D. Van Buuren, Michael Motsch, Gerhard RempeAbstract:A general method of cooling Polyatomic Molecules to ultracold temperatures is reported; the optoelectrical cooling technique removes kinetic energy via a Sisyphus effect, effectively causing the Molecules to continually ‘climb’ a hill of potential energy. Ultracold polar Molecules are of interest for various fundamental studies, including quantum-information science, ultracold chemistry and physics beyond the standard model. However, a general method for cooling Polyatomic Molecules to ultracold temperatures has been lacking. This paper demonstrates an optoelectrical cooling technique that can reduce the temperature of about a million methyl fluoride (CH3F) Molecules by a factor of more than ten. The scheme removes kinetic energy by means of a 'Sisyphus effect' that causes the Molecules to continually 'climb' a hill of potential energy. In contrast to other cooling mechanisms, it proceeds in a trap, cools in all three dimensions and should work for a large variety of polar Molecules. The chip-like trap and guide architecture used in this work are well suited to use in quantum-information processing with cold and ultracold Molecules. Polar Molecules have a rich internal structure and long-range dipole–dipole interactions, making them useful for quantum-controlled applications and fundamental investigations. Their potential fully unfolds at ultracold temperatures, where various effects are predicted in many-body physics1,2, quantum information science3,4, ultracold chemistry5,6 and physics beyond the standard model7,8. Whereas a wide range of methods to produce cold molecular ensembles have been developed9,10,11,12,13, the cooling of Polyatomic Molecules (that is, with three or more atoms) to ultracold temperatures has seemed intractable. Here we report the experimental realization of optoelectrical cooling14, a recently proposed cooling and accumulation method for polar Molecules. Its key attribute is the removal of a large fraction of a molecule’s kinetic energy in each cycle of the cooling sequence via a Sisyphus effect, allowing cooling with only a few repetitions of the dissipative decay process. We demonstrate the potential of optoelectrical cooling by reducing the temperature of about one million CH3F Molecules by a factor of 13.5, with the phase-space density increased by a factor of 29 (or a factor of 70 discounting trap losses). In contrast to other cooling mechanisms, our scheme proceeds in a trap, cools in all three dimensions and should work for a large variety of polar Molecules. With no fundamental temperature limit anticipated down to the photon-recoil temperature in the nanokelvin range, we expect our method to be able to produce ultracold Polyatomic Molecules. The low temperatures, large molecule numbers and long trapping times of up to 27 seconds should allow an interaction-dominated regime to be attained, enabling collision studies and investigation of evaporative cooling towards a Bose–Einstein condensate of Polyatomic Molecules.
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Sisyphus cooling of electrically trapped Polyatomic Molecules
Nature, 2012Co-Authors: Martin Zeppenfeld, Barbara G. U. Englert, Rosa Glöckner, Alexander Prehn, Manuel Mielenz, Christian Sommer, Michael Motsch, Laurens D. Van Buuren, Gerhard RempeAbstract:Polar Molecules have a rich internal structure and long-range dipole-dipole interactions, making them useful for quantum-controlled applications and fundamental investigations. Their potential fully unfolds at ultracold temperatures, where various effects are predicted in many-body physics, quantum information science, ultracold chemistry and physics beyond the standard model. Whereas a wide range of methods to produce cold molecular ensembles have been developed, the cooling of Polyatomic Molecules (that is, with three or more atoms) to ultracold temperatures has seemed intractable. Here we report the experimental realization of optoelectrical cooling, a recently proposed cooling and accumulation method for polar Molecules. Its key attribute is the removal of a large fraction of a molecule's kinetic energy in each cycle of the cooling sequence via a Sisyphus effect, allowing cooling with only a few repetitions of the dissipative decay process. We demonstrate the potential of optoelectrical cooling by reducing the temperature of about one million CH(3)F Molecules by a factor of 13.5, with the phase-space density increased by a factor of 29 (or a factor of 70 discounting trap losses). In contrast to other cooling mechanisms, our scheme proceeds in a trap, cools in all three dimensions and should work for a large variety of polar Molecules. With no fundamental temperature limit anticipated down to the photon-recoil temperature in the nanokelvin range, we expect our method to be able to produce ultracold Polyatomic Molecules. The low temperatures, large molecule numbers and long trapping times of up to 27 seconds should allow an interaction-dominated regime to be attained, enabling collision studies and investigation of evaporative cooling towards a Bose-Einstein condensate of Polyatomic Molecules.
