Isotopic shifts in ³P states of the carbon atom

Isotope shifts in the transition energies between several lowest (Formula presented.) states of the carbon atom are calculated at the nonrelativistic level of theory. We considered the (Formula presented.) C, (Formula presented.) C, and (Formula presented.) C isotopes, for which we performed variational calculations by expanding the wave functions of the atomic states in terms of all-electron explicitly correlated Gaussian functions. The Born–Oppenheimer approximation was not assumed in the calculations. By combining the computed isotope shifts with the experimentally derived Ritz wavelengths for the natural mixture of the isotopes we make predictions of the positions of the spectral lines for specific carbon isotopes. These predictions may be useful for guiding future experimental measurements of these lines using high-resolution spectroscopy.