18 research outputs found
High-resolution Laser Spectroscopy Of Lead Oxide (pbo) In 400-450 Nm
We observed rotationally resolved excitation spectra of PbO for transitions from the X(0) vibronic ground state
in a wavelength range of 400450 nm.
PbO molecules were produced by laser ablation in a cold helium buffer gas. The cold environment was useful to resolve overlapping rotational bands of different vibronic states.
Absolute transition frequencies were measured with the uncertainty of about 10 MHz
by using an ultralow expansion etalon for the laser frequency calibration.
Since the previous work [1], we have continued the measurement and have observed about 1000 lines so far.
The transitions to the B(1) (), A(0) (), and C(0) () states were clearly assigned,
and spectroscopic constants were determined precisely for three isotopic molecules PbO, PbO, and PbO.
We analyzed perturbation of the B(1) levels due to the spin-orbit interaction with other levels.
In this talk, we will present these results and analyses, including the latest data.
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[1] K. Enomoto, A. Fuwa, N. Hizawa, Y. Moriwaki, and K. Kobayashi, {\it J. Mol. Spectrosc.}, {\bf 339}, 12 (2017)
Schemes for nondestructive quantum gas microscopy of single atoms in an optical lattice
We propose a quantum gas microscope for ultracold atoms that enables nondestructive atom detection, thus evading higher-band excitation and change of the internal degrees of freedom. We show that photon absorption of a probe beam cannot be ignored even in dispersive detection to obtain a signal-to-noise ratio greater than unity because of the shot noise of the probe beam under a standard measurement condition. The first scheme we consider for the nondestructive detection, applicable to an atom that has an electronic ground state without spin degrees of freedom, is to utilize a magic-wavelength condition of the optical lattice for the transition for probing. The second is based on the dispersive Faraday effect and squeezed quantum noise and is applicable to an atom with spins in the ground state. In this second scheme, a scanning microscope is adopted to exploit the squeezed state and reduce the effective losses. Application to ultracold ytterbium atoms is discussed
Microwave Lens for Polar Molecules
We here report on the implementation of a microwave lens for neutral polar
molecules suitable to focus molecules both in low-field-seeking and in
high-field-seeking states. By using the TE_11m modes of a 12 cm long
cylindrically symmetric microwave resonator, Stark-decelerated ammonia
molecules are transversally confined. We investigate the focusing properties of
this microwave lens as a function of the molecules' velocity, the detuning of
the microwave frequency from the molecular resonance frequency, and the
microwave power. Such a microwave lens can be seen as a first important step
towards further microwave devices, such as decelerators and traps.Comment: 4 pages, 3 figure
Free-bound excitation and predissociation of ytterbium dimers near the ¹S₀-¹P₁ atomic transition
A continuous excitation band of a free-bound photoassociation transition of ytterbium atoms is observed as a red wing of the ¹S₀-¹P₁ atomic line at 399 nm for a hot thermal vapor. The excitation to the 0u⁺ molecular state is observed by monitoring fluorescence from the ³P₁ state atoms, which allows us to detect the production of Yb₂ molecules with high sensitivity. The photoassociation is characterized in comparison with transitions to atomic Rydberg states. The time profile of the fluorescence signal suggests that the 0u⁺ molecular state predissociates with states correlating to the ¹S₀+³D₂ atomic states
Two-color photoassociation spectroscopy of ytterbium atoms and the precise determinations of s-wave scattering lengths
By performing high-resolution two-color photoassociation spectroscopy, we
have successfully determined the binding energies of several of the last bound
states of the homonuclear dimers of six different isotopes of ytterbium. These
spectroscopic data are in excellent agreement with theoretical calculations
based on a simple model potential, which very precisely predicts the s-wave
scattering lengths of all 28 pairs of the seven stable isotopes. The s-wave
scattering lengths for collision of two atoms of the same isotopic species are
13.33(18) nm for ^{168}Yb, 3.38(11) nm for ^{170}Yb, -0.15(19) nm for ^{171}Yb,
-31.7(3.4) nm for ^{172}Yb, 10.55(11) nm for ^{173}Yb, 5.55(8) nm for ^{174}Yb,
and -1.28(23) nm for ^{176}Yb. The coefficient of the lead term of the
long-range van der Waals potential of the Yb_2 molecule is C_6=1932(30) atomic
units J nm^6).Comment: 9 pages, 7 figure
Low-J Transitions in A˜2Π(0,0,0)−X˜2Σ+(0,0,0) Band of Buffer-gas-cooled CaOH
Calcium monohydroxide radical (CaOH) is receiving an increasing amount of attention from the astrophysics community as it is expected to be present in the atmospheres of hot rocky super-Earth exoplanets as well as interstellar and circumstellar environments. Here, we report the high-resolution laboratory absorption spectroscopy on low-J transitions in
A
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band of buffer-gas-cooled CaOH. In total, 40 transitions out of the low-J states were assigned, including 27 transitions that have not been reported in previous literature. The determined rotational constants for both ground and excited states are in excellent agreement with previous literature, and the measurement uncertainty for the absolute transition frequencies was improved by more than a factor of 3. This will aid future interstellar, circumstellar, and atmospheric identifications of CaOH. The buffer-gas-cooling method employed here is a particularly powerful method to probe low-J transitions and is easily applicable to other astrophysical molecules.</jats:p
High-resolution spectroscopy of buffer-gas-cooled phthalocyanine
For over five decades, studies in the field of chemical physics and physical
chemistry have primarily aimed to understand the quantum properties of
molecules. However, high-resolution rovibronic spectroscopy has been limited to
relatively small and simple systems because translationally and rotationally
cold samples have not been prepared in sufficiently large quantities for large
and complex systems. In this study, we present high-resolution rovibronic
spectroscopy results for large gas-phase molecules, namely, free-base
phthalocyanine (FBPc). The findings suggest that buffer-gas cooling may be
effective for large molecules introduced via laser ablation. High-resolution
electronic spectroscopy, combined with other experimental and theoretical
studies, will be useful in understanding the quantum properties of molecules.
These findings also serve as a guide for quantum chemical calculations of large
molecules
Measurement of Doppler effects in a cryogenic buffer-gas cell
Buffer-gas cooling is a universal cooling technique for molecules and used for various purposes. One of its ap- plications is using molecules inside a buffer-gas cell for low-temperature spectroscopy. Although a high-intensity signal is expected in the cell, complex molecular dynamics is a drawback for precise spectroscopy. In this study, we performed high-resolution absorption spectroscopy of low -J transitions in the òΠ(0, 0, 0)-˜X²Σ+(0, 0, 0) band of calcium monohydroxide (CaOH). CaOH molecules were produced by laser ablation in a copper cell and cooled to ∼5 K using helium buffer gas. We probed the Doppler effects in a buffer-gas cell by injecting counterpropagating lasers inside the cell. The time evolutions of the Doppler width and shift were simulated using a dedicated Monte Carlo simulation and compared with data