| Abstrakt: |
The introduction of an off-diagonal spin–orbit interaction element in the Hamiltonian matrix representing the close-lying B 1Π and c 3Σ+ states of ScF allows us to interpret the anomalies previously observed, i.e., the large Λ-type doubling in B 1Π and the large spin-splitting in c 3Σ+ at v=0, both of which decrease rapidly with increasing vibration. Deperturbed molecular constants for the v=0,1,2 levels in both states, together with values of the interaction parameter, are obtained from the numerical treatment of the wave numbers of 1454 lines in the B 1Π→X 1Σ+(0-1), (1-1), (2-0), (2-2), and c 3Σ+→X 1Σ+(0-1), (1-0), (2-0) bands. The interaction between B 1Π and c 3Σ+ is greatest at v=0 and decreases rapidly with increasing v. The model of the states including hyperfine effects is then used to interpret the observed hyperfine structure which is attributed to strong interaction between the 4sσ3dσ electrons and the 45Sc nucleus of spin 7/2. The hyperfine structure of the rotational levels in B 1Π(v=0,1,2) and c 3Σ+(v=0,1,2) is thus investigated from analysis of the line profiles in the Q branches of the two systems, the only ones to exhibit measurable hyperfine broadenings at the resolution achieved by Fourier transform spectrometry of the thermal emission of ScF. Line profiles are synthesized by convolution of the apparatus function with the intensity weighted Doppler profiles attached to the multiplet components positioned at calculated energies. A value of the Fermi contact term, bF=0.032±0.008 cm-1, in c 3Σ+ is derived by matching the calculated profiles to the experimental ones. Hyperfine interactions nondiagonal in J are shown to be negligible. The present value of bF for ScF in the c 3Σ+ state agrees well with the corresponding value for ScO in its ground state. © 1995 American Institute of Physics. [ABSTRACT FROM AUTHOR] |
