Theoretical study on isotope-selective vibrational excitation of the lithium chloride molecule by optical pulses

Ichihara, Akira ; Yokoyama, Keiichi  

Recently, we proposed a method for isotope-selective rovibrational excitation of diatomic molecules by two kinds of optical pulses, for the isotope-separation of long-lived fission products produced in atomic energy power plants. In this method, rotational states of the molecules are excited isotope-selectively by using an optical frequency comb. Then, vibrational states of the molecules in high rotational states are excited by another optical pulse. In this study, we investigated how the second pulse shape affects the isotope-selective vibrational excitation using computer simulations based on the close-coupling method. The LiCl molecules were used as test molecules. The results indicated that the isotope-selective vibrational excitation is induced effectively by properly selecting spectral frequencies of the second pulse by referring to the transition frequencies in the P-branch of the selected isotope molecule.