We study the electronic and hyperfine structures of $^{24}\mathrm{MgH}$ molecule, which are of crucial importance for the laser cooling of the molecule. The accurate spectroscopic constants and hyperfine levels are presented for $X^{2}\mathrm{\ensuremath{\Sigma}}^{+}$ and $A^{2}\mathrm{\ensuremath{\Pi}}$ symmetries. The theoretical results are in good agreement with the experimental data. We then provide a scheme for the laser-driven cycling transitions of $A^{2}\mathrm{\ensuremath{\Pi}}_{1/2}\ensuremath{\leftarrow}X^{2}\mathrm{\ensuremath{\Sigma}}_{1/2}$. In addition, we calculate the hyperfine branching ratios for the rate of decay from $|A^{2}\mathrm{\ensuremath{\Pi}}_{1/2},{J}^{\ensuremath{'}}=1/2,+\ensuremath{\rangle}$ to $|X^{2}\mathrm{\ensuremath{\Sigma}}_{1/2},N=1,\ensuremath{-}\ensuremath{\rangle}$ transition. We also provide a sideband modulation scheme to the pumping lasers to match all four hyperfine levels of the $X^{2}\mathrm{\ensuremath{\Sigma}}_{1/2}$ ( $v=0$ , $N=1$ ). Finally, we calculate the Zeeman shift of the ($X^{2}\mathrm{\ensuremath{\Sigma}}_{1/2}$, $v=0$ , $N=1$ ) ground state, and the typical hyperfine structure magnetic $g$ factor ${g}_{F}$ and mixed $g$ factors ${g}_{F}^{\mathrm{eff}}$ are also calculated. Our study is expected to be useful for the laser-cooling $^{24}\mathrm{MgH}$ molecule and the interpretation of astronomical spectra involving MgH molecule.We study the electronic and hyperfine structures of $^{24}\mathrm{MgH}$ molecule, which are of crucial importance for the laser cooling of the molecule. The accurate spectroscopic constants and hyperfine levels are presented for $X^{2}\mathrm{\ensuremath{\Sigma}}^{+}$ and $A^{2}\mathrm{\ensuremath{\Pi}}$ symmetries. The theoretical results are in good agreement with the experimental data. We then provide a scheme for the laser-driven cycling transitions of $A^{2}\mathrm{\ensuremath{\Pi}}_{1/2}\ensuremath{\leftarrow}X^{2}\mathrm{\ensuremath{\Sigma}}_{1/2}$. In addition, we calculate the hyperfine branching ratios for the rate of decay from $|A^{2}\mathrm{\ensuremath{\Pi}}_{1/2},{J}^{\ensuremath{'}}=1/2,+\ensuremath{\rangle}$ to $|X^{2}\mathrm{\ensuremath{\Sigma}}_{1/2},N=1,\ensuremath{-}\ensuremath{\rangle}$ transition. We also provide a sideband modulation scheme to the pumping lasers to match all four hyperfine levels of the $X^{2}\mathrm{\ensuremath{\Sigma}}_{1/2}$ ($v=0$, $N=1$). Finally, we calculate the Zeeman shift of the ($X^{2}\mathrm{\ensuremath{\Sigma}}_{1/2}$, $v=0$, $N=1$) ground state, and the typical hyperfine structure magnetic $g$ factor ${g}_{F}$ and mixed $g$ factors ${g}_{F}^{\mathrm{eff}}$ are also calculated. Our study is expected to be useful for the laser-cooling $^{24}\mathrm{MgH}$ molecule and the interpretation of astronomical spectra involving MgH molecule.

Physical Review AOct 28, 20202 citations

Laser Cooling of Atoms

Hidekazu Hachisu

Nihon Kikai Gakkaishi/Journal of the Japan Society of Mechanical EngineersJan 1, 20090 citations

High-resolution Doppler laser spectroscopy of the laser cooling candidate La-

E. Jordan

The bound-bound transition from the 5d26s2 3Fe2 ground state to the 5d6s26p 3D° 2 excited state in negative lanthanum has been proposed as a candidate for laser cooling, which has not yet been achieved for negative ions. Anion laser cooling holds the potential to allow the production of ultracold ensembles of any negatively charged species. In this work the aforementioned transition was studied in a beam of negative La ions by high-resolution laser spectroscopy. The center-of-gravity frequency of the transition was measured to be 96.592 80(10) THz. Seven of the nine expected hyperfine structure resonances were resolved. The observed peaks were unambiguously assigned to the predicted hyperfine transitions by a fit. From the determined hyperfine structure for this transition it was concluded that only three lasers would be required to cool and re-pump all hyperfine levels. Furthermore, the observed relative transition amplitudes suggest that in resonance the transitions are saturated at a laser power of 45 Wm-2. A rough estimate of the transition cross section confirms that La- is a promising candidate for the first laser cooling of negative ions.The bound-bound transition from the 5d26s2 3Fe2 ground state to the 5d6s26p 3D° 2 excited state in negative lanthanum has been proposed as a candidate for laser cooling, which has not yet been achieved for negative ions. Anion laser cooling holds the potential to allow the production of ultracold ensembles of any negatively charged species. In this work the aforementioned transition was studied in a beam of negative La ions by high-resolution laser spectroscopy. The center-of-gravity frequency of the transition was measured to be 96.592 80(10) THz. Seven of the nine expected hyperfine structure resonances were resolved. The observed peaks were unambiguously assigned to the predicted hyperfine transitions by a fit. From the determined hyperfine structure for this transition it was concluded that only three lasers would be required to cool and re-pump all hyperfine levels. Furthermore, the observed relative transition amplitudes suggest that in resonance the transitions are saturated at a laser power of 45 Wm-2. A rough estimate of the transition cross section confirms that La- is a promising candidate for the first laser cooling of negative ions.

Nov 24, 20150 citations

High-resolution Doppler laser spectroscopy of the laser cooling candidate La-

Judith Elena Jordan

The bound-bound transition from the 5d²6s² ³F_2 ground state to the 5d6s²6p ³D_1 excited state in negative lanthanum has been proposed as a candidate for laser cooling, which has not yet been achieved for negative ions. Anion laser cooling holds the potential to allow the production of ultracold ensembles of any negatively charged species. In this work the aforementioned transition was studied in a beam of negative La ions by high-resolution laser spectroscopy. The center-of-gravity frequency of the transition was measured to be 96.592 80(10) THz. Seven of the nine expected hyperfine structure resonances were resolved. The observed peaks were unambiguously assigned to the predicted hyperfine transitions by a fit. From the determined hyperfine structure for this transition it was concluded that only three lasers would be required to cool and re-pump all hyperfine levels. Furthermore, the observed relative transition amplitudes suggest that in resonance the transitions are saturated at a laser power of 45 W/m². A rough estimate of the transition cross section confirms that La‾ is a promising candidate for the first laser cooling of negative ions.The bound-bound transition from the 5d²6s² ³F_2 ground state to the 5d6s²6p ³D_1 excited state in negative lanthanum has been proposed as a candidate for laser cooling, which has not yet been achieved for negative ions. Anion laser cooling holds the potential to allow the production of ultracold ensembles of any negatively charged species. In this work the aforementioned transition was studied in a beam of negative La ions by high-resolution laser spectroscopy. The center-of-gravity frequency of the transition was measured to be 96.592 80(10) THz. Seven of the nine expected hyperfine structure resonances were resolved. The observed peaks were unambiguously assigned to the predicted hyperfine transitions by a fit. From the determined hyperfine structure for this transition it was concluded that only three lasers would be required to cool and re-pump all hyperfine levels. Furthermore, the observed relative transition amplitudes suggest that in resonance the transitions are saturated at a laser power of 45 W/m². A rough estimate of the transition cross section confirms that La‾ is a promising candidate for the first laser cooling of negative ions.

Jan 1, 20151 citation

We study the electronic and hyperfine structures of

^{24}\mathrm{MgH}

molecule, which are of crucial importance for the laser cooling of the molecule. The accurate spectroscopic constants and hyperfine levels are presented for $X^{2}\mathrm{\ensuremath{\Sigma}}^{+}$ and $A^{2}\mathrm{\ensuremath{\Pi}}$ symmetries. The theoretical results are in good agreement with the experimental data. We then provide a scheme for the laser-driven cycling transitions of $A^{2}\mathrm{\ensuremath{\Pi}}_{1/2}\ensuremath{\leftarrow}X^{2}\mathrm{\ensuremath{\Sigma}}_{1/2}$. In addition, we calculate the hyperfine branching ratios for the rate of decay from $|A^{2}\mathrm{\ensuremath{\Pi}}_{1/2},{J}^{\ensuremath{'}}=1/2,+\ensuremath{\rangle}$ to $|X^{2}\mathrm{\ensuremath{\Sigma}}_{1/2},N=1,\ensuremath{-}\ensuremath{\rangle}$ transition. We also provide a sideband modulation scheme to the pumping lasers to match all four hyperfine levels of the $X^{2}\mathrm{\ensuremath{\Sigma}}_{1/2}$ (

v=0

N=1

). Finally, we calculate the Zeeman shift of the ($X^{2}\mathrm{\ensuremath{\Sigma}}_{1/2}$,

v=0

N=1

) ground state, and the typical hyperfine structure magnetic

g

factor

{g}_{F}

and mixed

g

factors

{g}_{F}^{\mathrm{eff}}

are also calculated. Our study is expected to be useful for the laser-cooling

^{24}\mathrm{MgH}

molecule and the interpretation of astronomical spectra involving MgH molecule.