Search

Using the effective rotational Hamiltonian method, we have conducted an analysis of the D218O ground and the first excited vibration state rotational energy levels. The analysis was based on the effective Hamiltonians represented in several forms: the Watson Hamiltonian, the Hamiltonian expressed in terms of Pad\'e-Borel approximants, and the Hamiltonian in terms of generating function expansions. The rotational and centrifugal constants have been determined from the fitting, which describe the rotational energy levels with an accuracy close to that of the experimental data. The predictive performance of the model with respect to highly excited rotational states has been evaluated against the global variation calculations. The radii of convergence of the effective rotation Hamiltonian series have been determined., Comment: 18 pages, 3 figures, 4 Tables

The rotational sublevels of the key (000) and (010) vibrational states of the H2S molecule were modeled with an accuracy close to experimental uncertainty using the generating function and Euler approaches. The predictive ability of the Hamiltonian parameters derived is tested against variational calculations. Comparison of transitions wavenumbers obtained from the presently calculated set of the H2S (000) and (010) energy levels with simulated (000)-(000), (010)-(010) transitions included in HITRAN 2016 database revealed a large discrepancy up to 44 cm-1. Large sets of accurate rotational sublevels of the (000) and (010) states are calculated., Comment: 14 pages, 4 figures, 3 tables