Accurate ab-Initio Quartic Force Fields for the Sulfur Compounds H2S, CS2, OCS, and CS

Rovibrationally Averaged Nuclear Shielding Constants in OCS

“…(41,42). Our WF3 results shown in Table 2 agree better with the more recent larger basis set cc-pVQZ results than with the previous cc-pVTZ values for all but one ( f rЈ ) parameter of the force field.…”

“…Generally, the agreement with experiment increases from WF1 to WF2 to WF3, and all parameters, apart from the harmonic bending frequency, 2 , are within 0.5% of the experiment at the final WF3 level (with WF1 and WF2 better values of 2 were obtained than with WF3). The accuracy of WF3 results other than 2 is comparable with CCSD(T)/cc-pVQZ numbers (41,42). We have performed the calculation of the shielding surfaces for three functions, WF1, WF2, and WF3; thus we may estimate the relationship between the differences in the potential and the differences in the rovibrational effects on the shielding.…”

“…Since our own potentials are accurate enough, it is obviously more consistent to use for each computed property surface the potential obtained with the corresponding wavefunction, and this is how all our results for the shielding discussed below were obtained. We have verified in a test calculation that using instead of the WF1 potential another one, derived from the CCSD(T)/cc-pVTZ calculation (41), has a minimal effect on the rovibrationally averaged shieldings calculated with the WF1 shielding derivatives (the difference at 300 K is 0.1 ppm for O, 0.03 ppm for C, and 0.3 ppm for S). …”

Fourier Transform Spectroscopy of Carbonyl Sulfide from 4800 to 8000 cm−1and New Global Analysis of16O12C32S☆

“…Another confirmation of the importance of this k 1113 interaction is given by the analysis of the previously described perturbation of the 40 (37), which confirms the few percent accuracy of such predictions. Because the k 113 parameter is highly correlated with many diagonal parameters (17) and so not well determined in our analysis, we decided 1 year ago to fix it at its ab initio value of Ϫ45.891 cm Ϫ1 (37).…”

H232S : First Observation of the (70±,0) Local Mode Pair and Updated Global Effective Vibrational Hamiltonian

“…We note good agreement between our α values and the ab initio values of Ref. (27). This initial set of predicted rotational constants was used at the first stage of the analysis.…”