The spectrum of radioactive water vapor: the H219O radio-isotopologue

Abstract

The absorption spectrum of H₂¹⁹O, a radioactive isotopologue of the water molecule, is predicted using variational nuclear motion calculated based on a high precision potential energy function and ab initio dipole moment surface. Vibrational - rotational energy levels and wave functions, line centers and Einstein coefficients for dipole transitions are calculated. Predicted transition wavenumbers are improved by extrapolating known empirical energy levels of the stable H₂¹⁶O, H₂¹⁷O and H₂¹⁸O isotopologues to H₂¹⁹O. A line list for possible atmospheric application is presented which includes air line broadening coefficients. The calculations span a wide spectral range covering infrared and visible wavelengths, and are appropriate for temperatures up to 1000 K. Windows suitable for observing absorption by H₂¹⁹O are identified and comparisons made with the infrared spectra of water vapor in natural abundance, H₂¹⁵O and H₂¹⁴O.