Laser-induced fluorescence and Optical/Stark spectroscopy of PtC

Abstract

Optical/Stark measurements have been performed on the (0,0) bands of both the A″ 1Σ+–X 1Σ+ system (ν0≈12 643 cm−1) and the A′ 1Π–X Σ+ system (ν0≈13 196 cm−1) of platinum monocarbide. The PtC molecules were produced in a pulsed supersonic molecular beam source following the reaction of laser ablated platinum vapor with a mixture of a few percent of methane in argon. The newly determined permanent electric dipole moments obtained are 1.94(2)D (A″ 1Σ+) and 1.919(9)D (A′ 1Π). These results are discussed in terms of a proposed molecular orbital correlation diagram for platinum containing diatomics. The laser-induced fluorescence spectrum of the (0,0)A″ 1Σ+–X 1Σ+ transition of PtC has been re-recorded at high resolution (full width of half-maximum ∼40 MHz) and analyzed to yield rotational constants for the four most abundant isotopomers of PtC, extending the previous analysis [Appelblad, Nilsson, and Scullman, Phys. Scr. 7, 65 (1973)]. The anomalously large value (∼15 MHz) for the newly derived nuclear-spin rotation parameter, CI(195Pt), for the A″ 1Σ+ state is discussed.