Towards cold collisions between dipolar OH and ND $_{3}$ molecules within a permanent magnetic trapTowards cold collisions between dipolar OH and ND$_{3}$ molecules within a permanent magnetic trap

Brian C. Sawyer, Benjamin Stuhl, Mark Yeo +2 more

Bulletin of the American Physical SocietyMay 21, 20090 citations

Magnetic trapping of Stark decelerated OH

Benjamin Lev, Brian C. Sawyer, Eric Hudson +6 more

Bulletin of the American Physical SocietyMar 7, 20070 citations

Magnetoelectrostatic Trapping of Ground State OH Molecules

Brian C. Sawyer, Benjamin Lev, Eric R. Hudson +4 more

We report magnetic confinement of neutral, ground state OH at a density of approximately 3 x 10(3) cm(-3) and temperature of approximately 30 mK. An adjustable electric field sufficiently large to polarize the OH is superimposed on the trap in various geometries, making an overall potential arising from both Zeeman and Stark effects. An effective molecular Hamiltonian is constructed, with Monte Carlo simulations accurately modeling the observed single-molecule dynamics in various trap configurations. Magnetic trapping of cold polar molecules under adjustable electric fields may enable study of low energy dipolar interactions.We report magnetic confinement of neutral, ground state OH at a density of approximately 3 x 10(3) cm(-3) and temperature of approximately 30 mK. An adjustable electric field sufficiently large to polarize the OH is superimposed on the trap in various geometries, making an overall potential arising from both Zeeman and Stark effects. An effective molecular Hamiltonian is constructed, with Monte Carlo simulations accurately modeling the observed single-molecule dynamics in various trap configurations. Magnetic trapping of cold polar molecules under adjustable electric fields may enable study of low energy dipolar interactions.

arXiv:physics/0702146Physical Review LettersJun 21, 2007164 citations

Magnetoelectrostatic trapping of neutral OH molecules

Brian C. Sawyer, Benjamin Stuhl, Benjamin Lev +3 more

Bulletin of the American Physical SocietyMar 10, 20080 citations

Cold Polar Molecules for Novel Collision Experiments at Low Energies

Brian C. Sawyer

Research in the field of cold polar molecules is progressing rapidly. An array of interesting\ntopics is being developed including precision measurement and fundamental tests, quantum phase transitions, and ultracold chemistry. In particular, dipolar molecules in well-defined quantum states enable exquisite control of their interactions via applied electric fields. The long-range, anisotropic interaction between dipolar molecules leads to new collision dynamics that could be used for novel collective effects, quantum state engineering, and information processing. The focus of this Thesis is the production of cold samples of neutral OH molecules via Stark deceleration and magnetic trapping for novel collision experiments. This novelty results from our combination of cold external beams and trapped target molecules which facilitates observation of dipolar effects as well as low temperature collision resonances. The large permanent electric dipole moment of OH allows us to precisely tune the lab-frame velocity of the molecular packets from ∼ 500 m/s to rest. We have magnetically trapped OH packets at the terminus of our Stark decelerator at a temperature of 70 mK and density of 106 cm−3. With improved understanding of Stark deceleration, we optimize the decelerator efficiency and its coupling to the magnetic trap. Our latest trap design uses permanent ring magnets to create a three-dimensional magnetic quadrupole field. Use of magnetically trapped OH molecules for collision experiments with external beams allow us the unique opportunity of observing both elastic and inelastic collisions. In addition, the trap confinement yields sensitivity to differential elastic cross sections at low collision energies. This open magnetic trap has allowed measurement of collision cross sections between trapped OH and external supersonic beams of He and D2, the latter of which is of astrophysical interest due to the role of H2-OH collisions in pumping interstellar OH megamasers. The combination of trapped OH molecules and temperature tuned beams of He and D2 has facilitated measurement of the lowest-energy D2-OH collision cross sections yet reported. More recently, we report the first observation of electric-field dependent cross sections between two different species of cold polar molecules - OH and ND3 - thereby demonstrating control over molecular scattering in the cold regime. By combining for the first time the production techniques of Stark deceleration and buffer gas cooling, we increase the molecular interaction time by∼ 105 over traditional crossed-beam experiments to gain enhanced sensitivity at the characteristic densities of cold molecule production.Research in the field of cold polar molecules is progressing rapidly. An array of interesting\ntopics is being developed including precision measurement and fundamental tests, quantum phase transitions, and ultracold chemistry. In particular, dipolar molecules in well-defined quantum states enable exquisite control of their interactions via applied electric fields. The long-range, anisotropic interaction between dipolar molecules leads to new collision dynamics that could be used for novel collective effects, quantum state engineering, and information processing. The focus of this Thesis is the production of cold samples of neutral OH molecules via Stark deceleration and magnetic trapping for novel collision experiments. This novelty results from our combination of cold external beams and trapped target molecules which facilitates observation of dipolar effects as well as low temperature collision resonances. The large permanent electric dipole moment of OH allows us to precisely tune the lab-frame velocity of the molecular packets from ∼ 500 m/s to rest. We have magnetically trapped OH packets at the terminus of our Stark decelerator at a temperature of 70 mK and density of 106 cm−3. With improved understanding of Stark deceleration, we optimize the decelerator efficiency and its coupling to the magnetic trap. Our latest trap design uses permanent ring magnets to create a three-dimensional magnetic quadrupole field. Use of magnetically trapped OH molecules for collision experiments with external beams allow us the unique opportunity of observing both elastic and inelastic collisions. In addition, the trap confinement yields sensitivity to differential elastic cross sections at low collision energies. This open magnetic trap has allowed measurement of collision cross sections between trapped OH and external supersonic beams of He and D2, the latter of which is of astrophysical interest due to the role of H2-OH collisions in pumping interstellar OH megamasers. The combination of trapped OH molecules and temperature tuned beams of He and D2 has facilitated measurement of the lowest-energy D2-OH collision cross sections yet reported. More recently, we report the first observation of electric-field dependent cross sections between two different species of cold polar molecules - OH and ND3 - thereby demonstrating control over molecular scattering in the cold regime. By combining for the first time the production techniques of Stark deceleration and buffer gas cooling, we increase the molecular interaction time by∼ 105 over traditional crossed-beam experiments to gain enhanced sensitivity at the characteristic densities of cold molecule production.

Jan 1, 20102 citations

Dipole electric resonance at magnetic sublevels

А. V. Golubev, Gennadij I. Khvostenko

OptSpJul 1, 19750 citations

Towards cold collisions between dipolar OH and ND

_{3}

molecules within a permanent magnetic trap