Optical n(p, T90) Measurement Suite 3: Results at \(\lambda = 1542\,\text{nm}\)

Single-isotherm n(p, T₉₀) results are reported for the gases Ar, N₂, H₂O, and D₂O at vacuum wavelength \(\lambda = 1542.383(1)\) nm. The argon and nitrogen isotherms were measured near 303 K; the water isotherms were measured near 373 K. Combined with the two previous articles of this series, the present results beget several insights via dispersion analyses. The argon result is highly consistent with static measurement plus ab initio calculation of dispersion polarizability. The nitrogen result is nominally consistent with one recent experiment and the dipole oscillator strength distributions, but the present work offers a refined estimate of the molar refractivity at optical wavelengths. For ordinary and heavy water, the dispersion trend is nominally consistent with existing liquid measurements. However, water’s absorption features in the near-infrared preclude a reliable comparison of the present result with literature.