You may also wish to search for items by Hayakashi.
Only one matching reference was found.
Hirao, T.; Hayakashi, S-I.; Yamamoto, S.; Saito, S., Microwave Spectrum of the PD2Radical in the2B1Ground Electronic State, J. Mol. Spectrosc., 1998, 187, 2, 153, https://doi.org/10.1006/jmsp.1997.7457 . [all data]