Knowledge Bank

The electronic spectrum of the H$2$PO radical has been identified by laser-induced fluorescence (LIF) and single vibronic level (SVL) emission techniques. The radical was produced in a pulsed electric discharge jet using a precursor mixture of phosphine (PH$3$) and carbon dioxide in high-pressure argon and the $B~$$2$A - $X~$$2$A electronic transition was detected in the 410-338 nm region. Low resolution LIF and SVL emission spectra of H$2$PO and D$2$PO have been recorded and the $a\prime$ vibrational frequencies have been determined in both states. High-resolution spectra of the 0$\mathrm{00}$ bands of H$2$PO and D$2$PO, which consist of strong $a$-type and weaker $c$-type components, were recorded. The spectra have been rotationally analyzed and the excited state molecular structure determined. The spectrum of H$2$PO will be discussed in comparison with the spectra of other phosphoryl and arsenyl radicals that have been recently studied in our laboratory.