Dunham Treatment Including Effects of the Born–Oppenheimer Breakdown for Open-Shell Diatomic Molecules in2Σ States

ExoMol line lists - I. The rovibrational spectrum of BeH, MgH and CaH in theX 2Σ+state

“…As far as the theoretical ro-vibronic studies on CaH are concerned, there have been attempts to refine PECs by fitting to available experimental energies or frequencies (Martin 1988;Uehara 1998;Urena et al 2000). However, previous ro-vibronic models did not include a proper description of different important couplings between electronic states.…”

Evaluation of Expansion Coefficients from Optimal Fitting Parameters for the Analysis of Spectra of Diatomic Molecules and an Application to LiH

“…In previous papers (18)(19)(20) we modified a model based on a scheme involving ω and B developed by Thompson et al (12) [1] in which µ is the reduced mass of a molecule and M a , M b , and m e are the masses of atoms A and B and the electron, respectively. Correction terms Similarly to Dunham's original function for potential energy (17),…”

“…These results were applied to LiH (18,19) and CaH molecules (20). Under the restriction of Watson's inseparability of Q a,b (r ) estimated values of fitting parameters for the corrections were considered to be effective, and we could not proceed (18)(19)(20) to relate values of fitting parameters to any physical quantities, e.g., molecular g J values, electric dipole moments, and matrix elements of operators.…”

“…Under the restriction of Watson's inseparability of Q a,b (r ) estimated values of fitting parameters for the corrections were considered to be effective, and we could not proceed (18)(19)(20) to relate values of fitting parameters to any physical quantities, e.g., molecular g J values, electric dipole moments, and matrix elements of operators. Evaluation of individual expansion coefficients for Q a,b (r ), R a,b (r ), and S a,b (r ) from fitting parameters is necessary to relate values of fitting parameters to those physical quantities which can be expressed with expansion coefficients.…”

“…Following their analytic approach for the Born-Oppenheimer corrections, we modified the ω and B scheme of a potential model by Thompson et al (12), with which we analyzed spectra of molecules (13)(14)(15), extending Dunham's treatment (16,17) for the Schrödinger equation based on Watson's effective Hamiltonian (2), and obtained a compact expression for the contributions from the correction terms in the Hamiltonian to the Dunham Y i j coefficients (18)(19)(20).…”