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Valery Milner - One of the best experts on this subject based on the ideXlab platform.
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Laser control of Molecular Rotation: Expanding the utility of an optical centrifuge
The Review of scientific instruments, 2020Co-Authors: Ian Macphail-bartley, Alexander A. Milner, Walter W. Wasserman, Valery MilnerAbstract:Since its invention in 1999, the optical centrifuge has become a powerful tool for controlling Molecular Rotation and studying Molecular dynamics and Molecular properties at extreme levels of Rotational excitation. This technique has been applied to a variety of Molecular species, from simple linear molecules to symmetric and asymmetric tops, to Molecular ions and chiral enantiomers. Properties of isolated ultrafast rotating molecules, the so-called Molecular superrotors, have been investigated, as well as their collisions with one another and the interaction with external fields. The ability of an optical centrifuge to spin a particular molecule of interest depends on both the Molecular structure and the parameters of the centrifuge laser pulse. An interplay between these two factors dictates the utility of an optical centrifuge in any specific application. Here, we discuss the strategy of assessing and adjusting the properties of the centrifuge to those of the Molecular rotors and describe two practical examples of optical centrifuges with very different characteristics, implemented experimentally in our laboratory.
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laser control of Molecular Rotation expanding the utility of an optical centrifuge
arXiv: Instrumentation and Detectors, 2019Co-Authors: Ian Macphailbartley, Alexander A. Milner, Walter Wasserman, Valery MilnerAbstract:Since its invention in 1999, optical centrifuge has become a powerful tool for controlling Molecular Rotation and studying Molecular dynamics and Molecular properties at extreme levels of Rotational excitation. The technique has been applied to a variety of Molecular species, from simple linear molecules to symmetric and asymmetric tops, to Molecular ions and chiral enantiomers. Properties of isolated ultrafast rotating molecules, so-called Molecular superrotors, have been investigated, as well as their collisions with one another and interaction with external fields. The ability of an optical centrifuge to spin a particular molecule of interest depends on both the Molecular structure and the parameters of the centrifuge laser pulse. An interplay between these two factors dictates the utility of an optical centrifuge in any specific application. Here, we discuss the strategy of assessing and adjusting the properties of the centrifuge to those of the Molecular rotors, and describe two practical examples of optical centrifuges with very different characteristics, implemented experimentally in our laboratory.
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observation of nondispersing classical like Molecular Rotation
arXiv: Chemical Physics, 2014Co-Authors: Aleksey Korobenko, J. W. Hepburn, Valery MilnerAbstract:Using the technique of an optical centrifuge, we produce Rotational wave packets which evolve in time along either classical-like or non-classical trajectories. After releasing O2 and D2 molecules from the centrifuge, we track their field-free Rotation by monitoring the Molecular angular distribution with velocity map imaging. Due to the dispersion of the created Rotational wave packets in oxygen, we observe a gradual transition between "dumbbell"-shaped and "cross"-shaped distributions, both rotating with a classical Rotation frequency. In deuterium, a much narrower Rotational wave packet is produced and shown to evolve in a truly classical non-dispersing fashion.
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Effects of ultrafast Molecular Rotation on collisional decoherence.
Physical review letters, 2014Co-Authors: Alexander A. Milner, Aleksey Korobenko, John W. Hepburn, Valery MilnerAbstract:Using an optical centrifuge to control Molecular Rotation in an extremely broad range of angular momenta, we study coherent Rotational dynamics of nitrogen molecules in the presence of collisions. We cover the range of Rotational quantum numbers between $J=8$ and $J=66$ at room temperature and study a crossover between the adiabatic and nonadiabatic regimes of Rotational relaxation, which cannot be easily accessed by thermal means. We demonstrate that the rate of Rotational decoherence changes by more than an order of magnitude in this range of $J$ values and show that its dependence on $J$ can be described by a simplified scaling law.
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control of Molecular Rotation with a chiral train of ultrashort pulses
Physical Review Letters, 2011Co-Authors: S Zhdanovich, J. W. Hepburn, Alexander A. Milner, Casey Bloomquist, Johannes Flos, Sh I Averbukh, Valery MilnerAbstract:Trains of ultrashort laser pulses separated by the time of Rotational revival (typically, tens of picoseconds) have been exploited for creating ensembles of aligned molecules. In this work we introduce a chiral pulse train--a sequence of linearly polarized pulses with the polarization direction rotating from pulse to pulse by a controllable angle. The chirality of such a train, expressed through the period and direction of its polarization Rotation, is used as a new control parameter for achieving selectivity and directionality of laser-induced Rotational excitation. The method employs chiral trains with a large number of pulses separated on the time scale much shorter than the Rotational revival (a few hundred femtosecond), enabling the use of conventional pulse shapers.
Ilya Sh Averbukh - One of the best experts on this subject based on the ideXlab platform.
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Observation of Bloch oscillations in Molecular Rotation
Physical Review Letters, 2015Co-Authors: Johannes Floß, Andrei Kamalov, Ilya Sh Averbukh, Philip H. BucksbaumAbstract:We report the observation of Rotational Bloch oscillations in a gas of nitrogen molecules kicked by a periodic train of femtosecond laser pulses. A controllable detuning from the quantum resonance creates an effective accelerating potential in angular momentum space, inducing Bloch-like oscillations of the Rotational excitation. These oscillations are measured via the temporal modulation of the refractive index of the gas. Our results introduce room-temperature laser-kicked molecules as a new laboratory for studies of localization phenomena in quantum transport.
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Anderson wall and BLOCH oscillations in Molecular Rotation.
Physical review letters, 2014Co-Authors: Johannes Floß, Ilya Sh AverbukhAbstract:We describe a universal behavior of linear molecules excited by a periodic train of short laser pulses under quantum resonance conditions. In a rigid rotor, the resonance causes an unlimited ballistic growth of the angular momentum. We show that the centrifugal distortion of rotating molecules eventually halts the growth, by causing Anderson localization beyond a critical value of the angular momentum--the Anderson wall. Its position solely depends on the Molecular Rotational constants and lies in the range of a few tens of ℏ. Below the wall, Rotational excitation oscillates with the number of pulses due to a mechanism similar to Bloch oscillations in crystalline solids. We suggest optical experiments capable of observing the Rotational Anderson wall and Bloch oscillations at near-ambient conditions with the help of existing laser technology.
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Controlling the sense of Molecular Rotation
New Journal of Physics, 2009Co-Authors: Sharly Fleischer, Yehiam Prior, Yuri Khodorkovsky, Ilya Sh AverbukhAbstract:We introduce a new scheme for controlling the sense of Molecular Rotation. By varying the polarization and the delay between two ultrashort laser pulses, we induce unidirectional Molecular Rotation, thereby forcing the molecules to rotate clockwise/counterclockwise under field-free conditions. We show that unidirectionally rotating molecules are confined to the plane defined by the two polarization vectors of the pulses, which leads to a permanent anisotropy in the Molecular angular distribution. The latter may be useful for controlling collisional cross-sections and optical and kinetic processes in Molecular gases. We discuss the application of this control scheme to individual components within a Molecular mixture in a selective manner.
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Field-free unidirectional Molecular Rotation
Springer Series in Chemical Physics, 2009Co-Authors: Sharly Fleischer, Ilya Sh Averbukh, Yehiam PriorAbstract:By varying the polarization and delay between two ultrashort laser pulses, we control the plane, speed, and sense of Molecular Rotation. This control may be implemented to individual components within a Molecular mixture.
Hajime Ito - One of the best experts on this subject based on the ideXlab platform.
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encapsulating n heterocyclic carbene binuclear transition metal complexes as a new platform for Molecular Rotation in crystalline solid state
Journal of the American Chemical Society, 2021Co-Authors: Mingoo Jin, Miguel A Garciagaribay, Rempei Ando, Marcus J Jellen, Hajime ItoAbstract:In crystalline solids, molecules generally have limited mobility due to their densely packed environment. However, structural information at the Molecular level may be used to design amphidynamic crystals with rotating elements linked to rigid, lattice-forming parts, which may lead to Molecular rotary motions and changes in conformation that determine the physical properties of the solid-state materials. Here, we report a novel design of emissive crystalline Molecular rotors with a central pyrazine rotator connected by implanted transition metals (Cu or Au) to a readily accessible enclosure formed by two N-heterocyclic carbenes (NHC) in discrete binuclear complexes. The activation energies for the Rotation could be tuned by changing the implanted metal. Exchanging Cu to Au resulted in an ∼4.0 kcal/mol reduction in the Rotational energy barrier as a result of lower steric demand by elongation of the axle with the noble metal, and a stronger electronic stabilization in the Rotational transition state by enhancement of the d-π* interactions between the metal centers and the pyrazine rotator. The Cu(I) rotor complex showed a greater electronic delocalization than the Au(I) rotor complex, causing a red-shifted solid-state emission. Molecular Rotation-induced emission quenching was observed in both crystals. The enclosing NHC rotors are easy to prepare, and their Rotational motion should be less dependent on packing structures, which are often crucial for many previously documented amphidynamic Molecular crystals. The platform from the encapsulating NHC cationic metal complexes and the metal-centered Rotation-axis provide a promising scaffold for a novel design of crystalline Molecular rotors, including manipulation of rotary dynamics and solid-state emission.
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phosphorescence control mediated by Molecular Rotation and aurophilic interactions in amphidynamic crystals of 1 4 bis tri p fluorophenyl phosphane gold i ethynyl benzene
Journal of the American Chemical Society, 2017Co-Authors: Mingoo Jin, Tim S Chung, Tomohiro Seki, Hajime Ito, Miguel A GarciagaribayAbstract:Here we present a structural design aimed at the control of phosphorescence emission as the result of changes in Molecular Rotation in a crystalline material. The proposed strategy includes the use of aurophilic interactions, both as a crystal engineering tool and as a sensitive emission probe, and the use of a dumbbell-shaped architecture intended to create a low packing density region that permits the Rotation of a central phenylene. Molecular rotor 1, with a central 1,4-diethynylphenylene rotator linked to two gold(I) triphenylphosphane complexes, was prepared and its structure confirmed by single-crystal X-ray diffraction, which revealed chains mediated by dimeric aurophilic interactions. We showed that green-emitting crystals exhibit reversible luminescent color changes between 298 and 193 K, which correlate with changes in Rotational motion determined by variable-temperature solid-state 2H NMR spin–echo experiments. Fast two-fold Rotation with a frequency of ca. 4.00 MHz (τ = 0.25 μs) at 298 K becom...
Alexander A. Milner - One of the best experts on this subject based on the ideXlab platform.
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Laser control of Molecular Rotation: Expanding the utility of an optical centrifuge
The Review of scientific instruments, 2020Co-Authors: Ian Macphail-bartley, Alexander A. Milner, Walter W. Wasserman, Valery MilnerAbstract:Since its invention in 1999, the optical centrifuge has become a powerful tool for controlling Molecular Rotation and studying Molecular dynamics and Molecular properties at extreme levels of Rotational excitation. This technique has been applied to a variety of Molecular species, from simple linear molecules to symmetric and asymmetric tops, to Molecular ions and chiral enantiomers. Properties of isolated ultrafast rotating molecules, the so-called Molecular superrotors, have been investigated, as well as their collisions with one another and the interaction with external fields. The ability of an optical centrifuge to spin a particular molecule of interest depends on both the Molecular structure and the parameters of the centrifuge laser pulse. An interplay between these two factors dictates the utility of an optical centrifuge in any specific application. Here, we discuss the strategy of assessing and adjusting the properties of the centrifuge to those of the Molecular rotors and describe two practical examples of optical centrifuges with very different characteristics, implemented experimentally in our laboratory.
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laser control of Molecular Rotation expanding the utility of an optical centrifuge
arXiv: Instrumentation and Detectors, 2019Co-Authors: Ian Macphailbartley, Alexander A. Milner, Walter Wasserman, Valery MilnerAbstract:Since its invention in 1999, optical centrifuge has become a powerful tool for controlling Molecular Rotation and studying Molecular dynamics and Molecular properties at extreme levels of Rotational excitation. The technique has been applied to a variety of Molecular species, from simple linear molecules to symmetric and asymmetric tops, to Molecular ions and chiral enantiomers. Properties of isolated ultrafast rotating molecules, so-called Molecular superrotors, have been investigated, as well as their collisions with one another and interaction with external fields. The ability of an optical centrifuge to spin a particular molecule of interest depends on both the Molecular structure and the parameters of the centrifuge laser pulse. An interplay between these two factors dictates the utility of an optical centrifuge in any specific application. Here, we discuss the strategy of assessing and adjusting the properties of the centrifuge to those of the Molecular rotors, and describe two practical examples of optical centrifuges with very different characteristics, implemented experimentally in our laboratory.
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Effects of ultrafast Molecular Rotation on collisional decoherence.
Physical review letters, 2014Co-Authors: Alexander A. Milner, Aleksey Korobenko, John W. Hepburn, Valery MilnerAbstract:Using an optical centrifuge to control Molecular Rotation in an extremely broad range of angular momenta, we study coherent Rotational dynamics of nitrogen molecules in the presence of collisions. We cover the range of Rotational quantum numbers between $J=8$ and $J=66$ at room temperature and study a crossover between the adiabatic and nonadiabatic regimes of Rotational relaxation, which cannot be easily accessed by thermal means. We demonstrate that the rate of Rotational decoherence changes by more than an order of magnitude in this range of $J$ values and show that its dependence on $J$ can be described by a simplified scaling law.
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control of Molecular Rotation with a chiral train of ultrashort pulses
Physical Review Letters, 2011Co-Authors: S Zhdanovich, J. W. Hepburn, Alexander A. Milner, Casey Bloomquist, Johannes Flos, Sh I Averbukh, Valery MilnerAbstract:Trains of ultrashort laser pulses separated by the time of Rotational revival (typically, tens of picoseconds) have been exploited for creating ensembles of aligned molecules. In this work we introduce a chiral pulse train--a sequence of linearly polarized pulses with the polarization direction rotating from pulse to pulse by a controllable angle. The chirality of such a train, expressed through the period and direction of its polarization Rotation, is used as a new control parameter for achieving selectivity and directionality of laser-induced Rotational excitation. The method employs chiral trains with a large number of pulses separated on the time scale much shorter than the Rotational revival (a few hundred femtosecond), enabling the use of conventional pulse shapers.
Claudia G. Giribet - One of the best experts on this subject based on the ideXlab platform.
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Theoretical study of the nuclear spin-Molecular Rotation coupling for relativistic electrons and non-relativistic nuclei
Journal of Chemical Physics, 2012Co-Authors: Ignacio Agustín Aucar, Sergio S. Gomez, Martín C. Ruiz De Azúa, Claudia G. GiribetAbstract:A theoretical study of the relation between the relativistic formulation of the nuclear magnetic shielding and spin-Rotation tensors is presented. To this end a theoretical expression of the relativistic spin-Rotation tensor is formulated, considering a Molecular Hamiltonian of relativistic electrons and non-relativistic nuclei. Molecular Rotation effects are introduced considering the terms of the Born-Oppenheimer decomposition, which couple the electrons and nuclei dynamics. The loss of the simple relation linking both spectral parameters in the non-relativistic formulation is further analyzed carrying out a perturbative expansion of relativistic effects by means of the linear response within the elimination of the small component approach. It is concluded that relativistic effects on the spin-Rotation tensor are less important than those of the nuclear magnetic shielding tensor.