A Theoretical Study of Photoabsorption Cross Sections of Na2

In the framework of quantum defect theory, we calculate photoabsorption cross sections of Na2+. Based on our calculations, there is an absorption window in the photoabsorption cross sections of Na2+, and more than one bump above the absorption window. The calculated photoabsorption cross sections provide an explanation for the abnormal bump in the experimental measurements of Hudson, which is a long-standing experimental puzzle.