Preparation And Spectral Measurement Of Ultracold Rubidium Molecules By Photoassociation

In the past days,scientists have successfully used the laser cooling technique to obtain ultracold atoms.Especially the Bose Einstein condensation?BEC?implementation,for the study of ultracold temperatures?below 1mK?may provide a quantum phenomenon,so ultracold physics has been aroused extensive attention.Compared to ultracold atoms.In the state level of ultracold molecules is more abundant,the field control is also more flexible.Ultracold molecules in quantum computing,quantum degenerate ultracold molecules and chemical,gas,measurement of fundamental physical constants,have important application of high precision molecular spectroscopy.In this paper,a dark magneto-optical trap experimental platform for ultracold rubidium atoms is established,and the photoassociating preparation of ultracold rubidium molecules is realized.The excited rubidium molecules are observed by atomic trap loss spectroscopy.The photoassociation spectra of ultracold rubidium molecules were measured,and the vibrational structures of rubidium long range O_u⁺states were studied in detail.The vibrational quantum numbers of the corresponding molecular states were calibrated,and a high precision rotation constant was obtained,combined with the LRB model.The potential energy curves of deep bound states areobtained by calculating theC₃ coefficients of long range state.1.A dark magneto-optic trap experimental device for ultracold rubidium atom is established.According to the basic principle of laser cooling and trapping atom,a saturable absorption spectrum device is built to lock the laser frequency.A dark magneto-optical trap device was built to transfer the ultra-cooled rubidium atoms to the lowest hyperfine state.The number of rubidium atoms is about 2×10⁸,the density is 3×10¹1 cm^-3,and the temperature is 100?K.2.The ultracold rubidium molecules were prepared by photoassociation.The ultracold rubidium atoms in the dark magneto-optical trap were prepared by photoassociation,and the spectral data in the range of 38 cm^-1 from the dissociation line of atoms were obtained by high resolution loss spectroscopy.The vibrational spectra of the corresponding O_u⁺states are obtained,and the corresponding rotation constants are obtained by fitting the rigid body model.3.The state data near the asymptotic line of Rb(5S_1/2+5P_1/2)are analyzed,and the obtained high resolution spectral data are fitted and calculated.Using the LeRoy-Bernstein formula,a more accurate long range C₃ coefficient is obtained.The corresponding potential energy curve is corrected.