Evaluation of the Laser Excitation Efficiency of B2Σ+ – X2Π Transition of Phosphorus Oxide

The article presents the results of calculation of vibrational and rotational terms of X2Π and B2Σ+ electronic states of phosphorus oxide (PO) molecule. The absorption spectrum corresponding to electronic transition B2Σ+ ( $${v}{\kern 1pt} '$$ = 0) – X2Π ( $${v}{\kern 1pt} ''$$ = 0) is calculated. The efficiency of laser excitation of PO molecules is estimated depending on the spectral parameters of radiation. It is established that the efficiency of excitation of the electronic transition B2Σ+ ( $${v}{\kern 1pt} '$$ = 0) – X2Π ( $${v}{\kern 1pt} ''$$ = 0) of PO molecule is approximately an order of magnitude lower than that of A2Σ+ ( $${v}{\kern 1pt} '$$ = 0) – X 2Π ( $${v}{\kern 1pt} ''$$ = 0) transition. The results are of practical importance from the point of view of choosing the optimal scheme for laser excitation of fluorescence of PO fragments in remote detection of organophosphates.