We demonstrate coherent microwave control of the rotational, hyperfine, and Zeeman states ultracold CaF molecules, magnetic trapping these molecules in a single, selectable quantum state. trap about $5\ifmmode\times\else\texttimes\fi{}{10}^{3}$ for almost 2 s at temperature $70(8)\text{ }\text{ }\ensuremath{\mu}\mathrm{K}$ density $1.2\ifmmode\times\else\texttimes\fi{}{10}^{5}\text{ }{\mathrm{cm}}^{\ensuremath{-}3}$. measure state-specific loss rate due to collisions with background helium.

Many modern theories predict that the fundamental constants depend on time, position, or local density of matter. We develop a spectroscopic method for pulsed beams cold molecules, and use it to measure frequencies microwave transitions in CH with accuracy down 3 Hz. By comparing these those measured from sources Milky Way, we test hypothesis may differ between high low environments Earth interstellar medium. For fine structure constant find \Delta\alpha/\alpha = (0.3 +/- 1.1)*10^{-7},...

Experiments with cold molecules usually begin a molecular source. We describe the construction and characteristics of cryogenic buffer gas source CaF molecules. The emits pulses typical duration 240 μs, mean speed about 150 m/s, flux 5×1010 per steradian pulse in single rotational state.

Here we report on spectroscopic measurements of the aluminum monofluoride molecule (AlF) that are relevant to laser cooling and trapping experiments. We measure detailed energy level structure AlF in X$^1\Sigma^+$ electronic ground state, A$^1\Pi$ metastable a$^3\Pi$ state. determine rotational, vibrational branching ratios from also study how rotational levels split shift external electric magnetic fields. find is an excellent candidate for any Q-line - transition at high densities.

Aluminium monofluoride (AlF) is a promising candidate for laser cooling and trapping at high densities. We show efficient production of AlF in bright, pulsed cryogenic buffer gas beam, demonstrate rapid optical cycling on the Q rotational lines $A^1Π\leftrightarrow X^1Σ^+ $ transition. measure brightness molecular beam to be $>10^{12}$ molecules per steradian pulse single state present new method determine its velocity distribution shot. The photon scattering rate scheme measured using...

The wave-particle duality of massive objects is a cornerstone quantum physics and key property many modern tools such as electron microscopy, neutron diffraction or atom interferometry. Here we report on the first experimental demonstration interference lithography with complex molecules. Molecular matter-wave patterns are deposited onto reconstructed Si(111) 7x7 surface imaged using scanning tunneling microscopy. Thereby both particle wave character molecules can be visualized in one same...

Using frequency-chirped radiation pressure slowing, we precisely control the velocity of a pulsed CaF molecular beam down to few m s–1, compressing its spread by factor 10 while retaining high intensity: at 15 s–1 flux, measured 1.3 from source, is 7 × 105 molecules per cm2 shot in single rovibrational state. The suitable for loading magneto-optical trap or, when combined with transverse laser cooling, improving precision spectroscopic measurements that test fundamental physics. We compare...

We report on hyperfine-resolved laser spectroscopy of the A2Π ← X2Σ+ transition magnesium monofluoride (MgF), relevant for cooling. recorded 25 rotational transitions with an absolute accuracy better than 20 MHz, assigned 56 hyperfine lines, and determined precise rotational, fine, structure parameters state. The radiative lifetime state was to be 7.2(3) ns, in good agreement ab initio calculations. isotope shift between bosonic isotopologues molecule is compared predicted values within...

We present the properties of a magneto-optical trap (MOT) CaF molecules. study process loading MOT from decelerated buffer-gas-cooled beam, and how best to slow this molecular beam in order capture most determine number molecules, photon scattering rate, oscillation frequency, damping constant, temperature, cloud size lifetime depend on key parameters MOT, especially intensity detuning main cooling laser. compare our results analytical numerical models, standard atomic MOTs, MOTs SrF load up...

Abstract Motivation The spectroscopy of diatomic molecules is an important research area in chemical physics due to its relevance astrochemistry, combustion chemistry, and ultracold physics. However, there currently no database where the user can easily retrieve, a useful format, spectroscopic constants given molecule. A similar situation appears concerning vibrational Franck–Condon factors for molecules, crucial parameter infer laser cooling prospects molecules. To address this problem,...

We present absolute frequency measurements of the ${}^{1}\text{P}_1 \leftarrow {}^{1}\text{S}_0$ ($229$nm) and ${}^{3}\text{P}_1 ($326$nm) transitions for all naturally occurring isotopes cadmium. The isotope shifts hyperfine intervals fermionic are determined with an accuracy 3.3MHz. find that quantum interference in laser-induced fluorescence spectra transition causes error up to 29(5)MHz determining splitting, when not accounted appropriate model. Using a King-plot analysis, we extract...

The simple structure of the BH molecule makes it an excellent candidate for direct laser cooling. We measure branching ratios decay A^{1}Pi (v'=0) state to vibrational levels ground state, X^{1}Sigma^{+}, and find that they are exceedingly favourable verify ratio spin-forbidden transition intermediate a^{3}Pi is inconsequentially small. frequency lowest rotational X hyperfine in relevant both A states, determine nuclear electric quadrupole magnetic dipole coupling constants. Our results show...

Cryogenic buffer gas beams are central to many cold molecule experiments. Here, we use absorption and fluorescence spectroscopy directly compare molecular of AlF, CaF, MgF, YbF molecules, produced by chemical reaction laser ablated atoms with fluorine rich reagents. The beam brightness for AlF is measured as $2\times 10^{12}$ molecules per steradian pulse in a single rotational state, comparable an Al atomic the same setup. MgF show order magnitude lower than far below Ca Yb beams. addition...

Abstract Isotope shifts (ISs) of atomic energy levels are sensitive probes nuclear structure and new physics beyond the standard model. We present an analysis ISs cadmium atom (Cd I) singly charged ion II). 229 nm, 326 361 nm 480 lines Cd I measured with a variety techniques; buffer–gas-cooled beam spectroscopy, capturing atoms in magneto-optic-trap, optical pumping. IS constants for D 1 2 II calculated high accuracy by employing analytical response relativistic coupled-cluster theory...

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We report absolute frequency, isotope shift, radiative lifetime, and hyperfine structure measurements of the <a:math...

The CH radical offers a sensitive way to test the hypothesis that fundamental constants measured on earth may differ from those observed in other parts of universe. starting point for such comparison is have accurate laboratory frequencies. Here we measure frequency lowest millimetre-wave transition CH, near 535 GHz, with an accuracy 0.6 kHz. This improves uncertainty by roughly two orders magnitude over previous determinations and opens new tests varying constants.

The Λ-doublet transitions in CH at 3.3 and 0.7 GHz are unusually sensitive to variations the fine-structure constant electron-to-proton mass ratio. We describe methods used measure frequencies of these with Hz-level accuracy. produce a pulsed supersonic beam cold by photodissociation CHBr3, we microwave transition as molecules propagate through parallel-plate transmission line resonator. use map out amplitude phase standing wave field inside line. investigate velocity-dependent frequency...

We characterize a Fabry–Pérot microwave cavity designed for trapping atoms and molecules at the antinode of field. The is fed from waveguide through small coupling hole. Focussing on compact resonant modes cavity, we measure how electric field profile, quality factor, efficiency, depend radius factor depends temperature mirrors in range 77 to 293 K. presence hole slightly changes profile mode, leading increased diffraction losses around edges reduction factor. find size that maximizes...

Spectroscopic studies of aluminum monofluoride (AlF) have revealed its highly favorable properties for direct laser cooling. All Q lines the strong A1Π ← X1Σ+ transition around 227 nm are rotationally closed and thereby suitable main cooling cycle. The same holds narrow, spin-forbidden a3Π 367 nm, which has a recoil limit in µK range. We here report on spectroscopic characterization lowest rotational levels state AlF v = 0-8 using jet-cooled, pulsed molecular beam. An accidental AC Stark...

In this work, we explore the role of chemical reactions on properties buffer gas cooled molecular beams. particular, focus scenarios relevant to formation AlF and CaF via between Ca Al atoms ablated from a solid target in an atmosphere fluorine-containing gas, case, SF6 NF3. Reactions are studied following ab initio dynamics approach, results rationalized tree-shaped reaction model based Bayesian inference. We find that NF3 reacts more efficiently with hot metal form monofluoride molecules...

Aluminum monofluoride (AlF) possesses highly favorable properties for laser cooling, both via the A1Π and a3Π states. Determining efficient pathways between singlet triplet manifold of electronic states will be advantageous future experiments at ultralow temperatures. The lowest rotational levels A1Π, v = 6 b3Σ+, 5 AlF are nearly iso-energetic interact spin-orbit coupling. These thus have a strongly mixed spin-character provide singlet-triplet doorway. We here present hyperfine resolved...

We investigated helium-mediated translational and rotational thermalization of the aluminum monofluoride (AlF) molecule at cryogenic temperatures via a new $ab \ initio$ potential energy surface (PES) quantum multichannel scattering theory. Our examination elastic rotationally inelastic channels revealed that helium is an efficient quencher AlF relevant to buffer gas cooling experiments ($\sim1$ mK $10$ K). also showed this conclusion robust against possible inaccuracies PES.