Resonant Auger decay study of core-excited OCS

The present work aims at characterizing short-lived C1s⁽⁻¹⁾π^*(1) core-excited states of the OCS molecule based on the analysis of the vibrational fine structure and lineshape profiles of the high-resolution resonant Auger decay spectra recorded at the excitation energies along the C1s→π^* resonance in the binding energy region 15–19 eV. Very different behavior in terms of lineshape and resonant enhancement is observed for the , and final states. This is explained by (1) the variation in the C–O bond lengths for the states involved in the electronic relaxation and (2) different contributions in terms of Mulliken population to the molecular orbitals determining the electronic character of the corresponding states. Since the final-state geometries are known from a number of previous experiments and ab initio calculations, the geometry of the C1s⁽⁻¹⁾π^*(1) intermediate states can be predicted in analogy with e.g. the N₂, CO₂ and N₂O molecules.     

Rovibrationally Averaged Nuclear Shielding Constants in OCS

The nuclear shielding constants in OCS are studied using ab initio theoretical methods and gas-phase NMR measurements. The shielding surfaces are calculated and the rovibrational effects and the resulting temperature dependence are analyzed. The temperature dependence of¹³C shielding in the gas phase is determined experimentally in the range 278–373 K.¹³C is the single nucleus for which the experimental data for the temperature dependence can be converted to a reference-independent scale, and good agreement of the measured and calculated ab initio results is observed. For³³S, we discuss a new, more accurate absolute shielding scale.     

射流冷却的OCS分子高分辨VUV吸收光谱研究

The absorption spectrum of OCS molecules under jet-cooled conditions has been measured between 64150 and 65840 cm-1 with a highly resolved tunable vacuum ultraviolet (VUV) laser (about 0.2 cm-1), generated by two-photon resonant four wave mixing process. During the experiment, the VUV intensities prior and posterior to the OCS absorption were monitored simultaneously in order to increase the sensitivity of absorption measurement, and the absorption sensitivity △I/I was determined to be 1%. The measured spectrum is essentially similar to the S(1S) photofragment excitation spectrum under similar conditions, indicating that the dissociation to produce S(1S) fragment is the main pathway. The difference between these kinds of spectra, however, implies the existence of other dissociation channels in addition to the S(1S) pathway.