ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
Ab initio configuration interaction calculations are carried out for eight low-lying 1,3Πu and four 1Δu states of the O2 molecule. Three different types of couplings are considered: nonadiabatic, spin–orbit, and rotational, and the complex scaling method has been employed to determine rovibrational energies and wave functions. The calculations correctly predict a large number of trends in the measured level locations, predissociation linewidths, rotational constants, and line intensities for the (4pσ) 1,3Πu states. It is found that the v=1 level has the lowest frequency and strongest absorption intensity among the four observed vibrational levels of the (4pσ) 3Πu state, while the v=2 has the broadest predissociation linewidth and v=0, the smallest rotational constant, all in agreement with experimental findings. The linewidth of the v=0 level of the 1Πu state is computed to be 0.01 cm−1, consistent with the measured value of less than 0.1 cm−1. The calculations indicate that the v=0 level of the (4pσ) 1Πu state borrows intensity from the allowed (4pσ) 3Πu–X 3Σg− through spin–orbit interaction and that the v=4 level of the (4pσ) 3Π1u component, which has not yet been identified experimentally, is strongly perturbed by the v=3 level of the (4pσ) 1Πu state. The L-uncoupling-type interaction between 1Πu and 1Δu states is also studied, and the explanation for the missing lines of the v=0, J≥2 rovibrational levels of the (4pσ) 1Πu states is sought based on the calculated results. © 1998 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.476252
