Triple TransitionQ1(j1)+Q1(j2)+Q1(j3)near 12 466cm−1in Compressed Hydrogen

We use the model of the overlap-induced, irreducible, ternary dipole (OITD) component of three interacting ${\mathrm{H}}_2$ molecules [Phys. Rev. A 49, 4508 (1994)] to calculate the intensity of the triple $Q_1$ transition, observed by Reddy, Xiang, and Vaghese [following Letter, Phys. Rev. Lett. 74, 367 (1995)] in compressed hydrogen gas in absorption near 12 466 ${\mathrm{cm}}^{-1\mathrm{}}$. Such simultaneous transitions in three interacting molecules are thought to arise from irreducible, ternary dipole components. The calculated intensities agree with the measurement within a factor of 2 or 3, which shows once more that the OITD model is capable of describing ternary spectroscopic interaction in remarkable detail.