Electronic transitions of yttrium monophosphide

Abstract

The electronic transition spectrum of the yttrium monophosphide (YP) molecule in the near infrared region between 715nm and 880nm has been recorded using laser ablation/reaction free-jet expansion and laser induced fluorescence spectroscopy. The YP molecule was produced by reacting laser – ablated yttrium atoms with PH3 gas seeded in argon. Eleven vibrational bands were analyzed and six electronic transitions have been identified, namely the [12.17] Ω=3 – X3Π2, [13.27] Ω=3 – X3Π2, [13.44] Ω=3 – X3Π2, [13.46] Ω=3 – X3Π2 and [13.40] Ω=2 – X3Π2 transitions and a [13.69] Ω=3 – a1Δ2 transition. Least squares fits of the measured rotational lines yielded molecular constants for the ground and excited states. The ground state has been determined to be a X3Π2 state and the bond length ro and vibrational separation, ΔG1/2, were determined to be 2.4413Å and 390.77cm−1 respectively. A molecular orbital energy level diagram has been used to aid the assignment of the observed electronic states. This work represents the first experimental investigation of the electronic spectrum of the YP molecule.