79 results found
Truppe S, Hambach M, Skoff S, et al., A buffer gas beam source for short, intense and slow molecular pulses, Journal of Modern Optics, ISSN: 0950-0340
Experiments with cold molecules usually begin with a molecular source. We describe the construction and characteristics of a cryogenic buff er gas source of CaF molecules. The source emits pulses with a typical duration of 240 μs, a mean speed of about 150 m/s, and a flux of 5x 10¹⁰ molecules per steradian per pulse in a single rotational state.
Williams H, Truppe S, Hambach M, et al., Characteristics of a magneto-optical trap of molecules, New Journal of Physics, ISSN: 1367-2630
We present the properties of a magneto-optical trap (MOT) of CaFmolecules. We study the process of loading the MOT from a decelerated bu er-gas-cooled beam, and how best to slow this molecular beam in order to capture the most molecules. We determine how the number of molecules, the photon scattering rate, the oscillation frequency, damping constant, temperature, cloud size and lifetime depend on the key parameters of the MOT, especially the intensity and detuning of the main cooling laser. We compare our results to analytical and numerical models, to the properties of standard atomic MOTs, and to MOTs of SrF molecules. We load up to 2 x 10⁴ molecules, and measure a maximum scattering rate of 2.5 x 10⁶ s⁻¹ per molecule, a maximum oscillation frequency of 100 Hz, a maximum damping constant of 500 s⁻¹, and a minimum MOT rms radius of 1.5 mm. A minimum temperature of 730 μK is obtained by ramping down the laser intensity to low values. The lifetime, typically about 100 ms, is consistent with a leak out of the cooling cycle with a branching ratio of about 6 x 10⁻⁶. The MOT has a capture velocity of about 11 m/s.
Williams H, Truppe S, Hambach M, et al., Characteristics of a magneto-optical trap of molecules, New Journal of Physics
Asselin P, Berger Y, Huet TR, et al., 2017, Characterising molecules for fundamental physics: an accurate spectroscopic model of methyltrioxorhenium derived from new infrared and millimetre-wave measurements, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, Vol: 19, Pages: 4576-4587, ISSN: 1463-9076
Asselin P, Berger Y, Huet TR, et al., 2017, Characterising molecules for fundamental physics: an accurate spectroscopic model of methyltrioxorhenium derived from new infrared and millimetre-wave measurements, Physical Chemistry Chemical Physics, Vol: 19, Pages: 4576-4587, ISSN: 1463-9084
Precise spectroscopic analysis of polyatomic molecules enables many striking advances in physical chemistry and fundamental physics. We use several new high-resolution spectroscopic devices to improve our understanding of the rotational and rovibrational structure of methyltrioxorhenium (MTO), the achiral parent of a family of large oxorhenium compounds that are ideal candidate species for a planned measurement of parity violation in chiral molecules. Using millimetre-wave and infrared spectroscopy in a pulsed supersonic jet, a cryogenic buffer gas cell, and room temperature absorption cells, we probe the ground state and the Re[double bond, length as m-dash]O antisymmetric and symmetric stretching excited states of both CH3187ReO3 and CH3185ReO3 isotopologues in the gas phase with unprecedented precision. By extending the rotational spectra to the 150–300 GHz range, we characterize the ground state rotational and hyperfine structure up to J = 43 and K = 41, resulting in refinements to the rotational, quartic and hyperfine parameters, and the determination of sextic parameters and a centrifugal distortion correction to the quadrupolar hyperfine constant. We obtain rovibrational data for temperatures between 6 and 300 K in the 970–1015 cm−1 range, at resolutions down to 8 MHz and accuracies of 30 MHz. We use these data to determine more precise excited-state rotational, Coriolis and quartic parameters, as well as the ground-state centrifugal distortion parameter DK of the 187Re isotopologue. We also account for hyperfine structure in the rovibrational transitions and hence determine the upper state rhenium atom quadrupole coupling constant eQq′.
Lim J, Almond JR, Tarbutt MR, et al., 2017, The -X-2 Sigma(+) and -X-2 Sigma(+) bands of ytterbium fluoride, (YbF)-Yb-174, JOURNAL OF MOLECULAR SPECTROSCOPY, Vol: 338, Pages: 81-90, ISSN: 0022-2852
Tokunaga SK, Hendricks RJ, Tarbutt MR, et al., 2017, High-resolution mid-infrared spectroscopy of buffer-gas-cooled methyltrioxorhenium molecules, NEW JOURNAL OF PHYSICS, Vol: 19, ISSN: 1367-2630
Truppe S, Williams H, Fitch N, et al., 2017, An intense, cold, velocity-controlled molecular beam by frequency-chirpedlaser slowing, New Journal of Physics, Vol: 19, ISSN: 1367-2630
Using frequency-chirped radiation pressure slowing, we precisely controlthe velocity of a pulsed CaF molecular beam down to a few m/s, compressing its velocity spread by a factor of 10 while retaining high intensity: at a velocity of 15 m/s the flux, measured 1.3 m from the source, is 7×10⁵ molecules per cm² per shot in a single rovibrational state. The beam is suitable for loading a magneto-optical trap or, when combined with transverse laser cooling, improving the precision of spectroscopicmeasurements that test fundamental physics. We compare the frequency-chirped slowing method with the more commonly used frequency-broadened slowing method.
Truppe S, Williams HJ, Fitch NJ, et al., 2017, An intense, cold, velocity-controlled molecular beam by frequency-chirped laser slowing, NEW JOURNAL OF PHYSICS, Vol: 19, ISSN: 1367-2630
The ability to cool atoms below the Doppler limit -- the minimum temperaturereachable by Doppler cooling -- has been essential to most experiments withquantum degenerate gases, optical lattices and atomic fountains, among manyother applications. A broad set of new applications await ultracold molecules,and the extension of laser cooling to molecules has begun. A molecularmagneto-optical trap has been demonstrated, where molecules approached theDoppler limit. However, the sub-Doppler temperatures required for mostapplications have not yet been reached. Here we cool molecules to 50 uK, wellbelow the Doppler limit, using a three-dimensional optical molasses. Theseultracold molecules could be loaded into optical tweezers to trap arbitraryarrays for quantum simulation, launched into a molecular fountain for testingfundamental physics, and used to study ultracold collisions and ultracoldchemistry.
Devlin JA, Tarbutt MR, 2016, Three-dimensional Doppler, polarization-gradient, and magneto-optical forces for atoms and molecules with dark states, NEW JOURNAL OF PHYSICS, Vol: 18, ISSN: 1367-2630
Fitch NJ, Tarbutt MR, 2016, Principles and Design of a Zeeman-Sisyphus Decelerator for Molecular Beams, CHEMPHYSCHEM, Vol: 17, Pages: 3609-3623, ISSN: 1439-4235
Fitch NJ, Tarbutt MR, 2016, Inside Cover: Principles and Design of a Zeeman-Sisyphus Decelerator for Molecular Beams (ChemPhysChem 22/2016), ChemPhysChem, Vol: 17, Pages: 3579-3579, ISSN: 1439-4235
Guttridge A, Hopkins SA, Kemp SL, et al., 2016, Direct loading of a large Yb MOT on the S-1(0) -> P-3(1) transition, JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS, Vol: 49, ISSN: 0953-4075
Hopkins SA, Butler K, Guttridge A, et al., 2016, A versatile dual-species Zeeman slower for caesium and ytterbium, REVIEW OF SCIENTIFIC INSTRUMENTS, Vol: 87, ISSN: 0034-6748
Hopkins SA, Butler K, Guttridge A, et al., 2016, A versatile dual-species Zeeman slower for caesium and ytterbium (vol 87, 043109, 2016), REVIEW OF SCIENTIFIC INSTRUMENTS, Vol: 87, ISSN: 0034-6748
Kemp SL, Butler KL, Freytag R, et al., 2016, Production and characterization of a dual species magneto-optical trap of cesium and ytterbium, REVIEW OF SCIENTIFIC INSTRUMENTS, Vol: 87, ISSN: 0034-6748
Norrgard EB, McCarron DJ, Steinecker MH, et al., 2016, Submillikelvin Dipolar Molecules in a Radio-Frequency Magneto-Optical Trap, PHYSICAL REVIEW LETTERS, Vol: 116, ISSN: 0031-9007
Devlin J, Tarbutt MR, Kokkin DL, et al., 2015, Measurements of the Zeeman effect in the A(2)Pi and B-2 Sigma(+) states of calcium fluoride, JOURNAL OF MOLECULAR SPECTROSCOPY, Vol: 317, Pages: 1-9, ISSN: 0022-2852
Dunseith DP, Truppe S, Hendricks RJ, et al., 2015, A high quality, efficiently coupled microwave cavity for trapping cold molecules, JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS, Vol: 48, ISSN: 0953-4075
Lim J, Frye MD, Hutson JM, et al., 2015, Modeling sympathetic cooling of molecules by ultracold atoms, PHYSICAL REVIEW A, Vol: 92, ISSN: 2469-9926
Tarbutt MR, 2015, Magneto-optical trapping forces for atoms and molecules with complex level structures, NEW JOURNAL OF PHYSICS, Vol: 17, ISSN: 1367-2630
Tarbutt MR, Steimle TC, 2015, Modeling magneto-optical trapping of CaF molecules, PHYSICAL REVIEW A, Vol: 92, ISSN: 1050-2947
Hendricks RJ, Holland DA, Truppe S, et al., 2014, Vibrational branching ratios and hyperfine structure of <sup>11</sup>BH and its suitability for laser cooling, Frontiers of Physics, Vol: 2, Pages: 1-8, ISSN: 2095-0462
© 2014 Hendricks, Holland, Truppe, Sauer and Tarbutt. The simple structure of the BH molecule makes it an excellent candidate for direct laser cooling. We measure the branching ratios for the decay of the A 1 Π (v ′ = 0) state to vibrational levels of the ground state, X 1 Σ + , and find that they are exceedingly favorable for laser cooling. We verify that the branching ratio for the spin-forbidden transition to the intermediate a 3 Π state is inconsequentially small. We measure the frequency of the lowest rotational transition of the X state, and the hyperfine structure in the relevant levels of both the X and A states, and determine the nuclear electric quadrupole and magnetic dipole coupling constants. Our results show that, with a relatively simple laser cooling scheme, a Zeeman slower and magneto-optical trap can be used to cool, slow and trap BH molecules.
Smallman IJ, Wang F, Steimle TC, et al., 2014, Radiative branching ratios for excited states of (YbF)-Yb-174: Application to laser cooling, JOURNAL OF MOLECULAR SPECTROSCOPY, Vol: 300, Pages: 3-6, ISSN: 0022-2852
Truppe S, Hendricks RJ, Hinds EA, et al., 2014, MEASUREMENT OF THE LOWEST MILLIMETER-WAVE TRANSITION FREQUENCY OF THE CH RADICAL, ASTROPHYSICAL JOURNAL, Vol: 780, ISSN: 0004-637X
Truppe S, Hendricks RJ, Tokunaga SK, et al., 2014, Microwave spectroscopy of A-doublet transitions in the ground state of CH, JOURNAL OF MOLECULAR SPECTROSCOPY, Vol: 300, Pages: 70-78, ISSN: 0022-2852
Bulleid NE, Skoff SM, Hendricks RJ, et al., 2013, Characterization of a cryogenic beam source for atoms and molecules, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, Vol: 15, Pages: 12299-12307, ISSN: 1463-9076
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