Analysis of Pure Rotational and Vibration‐rotational Spectra of NaCl X 1Σ+ and Quantum‐chemical Calculation of Related Molecular Properties

We fitted published frequency and wave number data for pure rotational and vibration‐rotational spectra, respectively, of ²³Na³⁵Cl and ²³Na³⁷Cl to derive parameters related to potential energy and to the rotational g factor. For comparison with these experimental data we undertook quantum‐chemical computation of adiabatic corrections, rotational and vibrational g factors, electric dipolar moment and its derivative as a function of internuclear distance in a range near R_e as a test of an algebraic approach to spectral analysis; experimental, 0.0287 ± 0.0014, and calculated, 0.02149, values of g_r at R_e are in moderate agreement. The combined results are discussed from a point of view of computational spectrometry.