Theoretical studies of the low-lying electronic states of GaKr, including extrapolation to InKr and TlKr

Abstract

We report ab initio configuration interfaction calculations on the states of the gallium krypton (GaKr) molecule arising from the Ga(2P1/2,3/2,2S1/2) + Kr(1SO) and Ga+(1SO) + Kr(1SO) separated atom limits. The potential energy curves for the states arising from the Ga(2P1/2,3/2) limits, the I 1/2, II 1/2, and I 3/2 states, are found to be repulsive. The potential energy curves for the states arising from the Ga(2S1/2) and Ga+(1SO) limits, the III 1/2 and I 0 states, are both found to be weakly bound; De (III 1/2) = 0.047 eV and D (I 0) = 0.24 eV. The potential energy curves and transition moments obtained in the GaKr calculations have been used to simulate the curves and moments for InKr and TlKr. Using this data the absorption and emission coefficients of all three molecules have been calculated.

Theoretical Study of M+−RG Complexes (M = Ga, In; RG = He−Rn)

“…It could be that there is not enough dynamic correlation in the previous calculation, as the basis set employed there was quite large; even so, the discrepancy is far larger than one might have anticipated. On the other hand, the polarized CI (POL-CI) calculations of Dunning et al 15 for Ga þ ÀKr are in much better agreement with the present calculations, although the absolute differences are still significant. The large basis sets employed in the present work, and our use of the CCSD(T) method, would suggest that the present results are the more reliable.…”

“…In Table are presented the calculated spectroscopic parameters for the Ga + −RG complexes, from the present work. Also shown are what appear to be the only previously reported results for these cations: the CASSCF+MRCI results for Ga + −Ar and the CI results for Ga + −Kr . As may be seen for Ga + −Ar, the agreement between the present results and the CASSCF+MRCI ones is extremely poor, with the previous D e value being only about 50% of the present value, and the ω e value being significantly smaller also.…”

“…Also shown are what appear to be the only previously reported results for these cations: the CASSCFþMRCI results for Ga þ ÀAr 16 and the CI results for Ga þ ÀKr. 15 As may be seen for Ga þ ÀAr, the agreement between the present results and the CASSCFþMRCI ones is extremely poor, with the previous D e value being only about 50% of the present value, and the ω e value being significantly smaller also. It could be that there is not enough dynamic correlation in the previous calculation, as the basis set employed there was quite large; even so, the discrepancy is far larger than one might have anticipated.…”

“… a The quantities refer to the following isotopes: 69 Ga, 4 He, 20 Ne, 40 Ar, 84 Kr, 132 Xe, and 222 Rn. R e is the equilibrium bond length, D e is the depth of the potential, D 0 is the difference in energy between the zero-point and the Ga + ( 1 S) + RG( 1 S) asymptote, ω e is the harmonic vibrational frequency, ω e x e is the anharmonicity constant, B e is the equilibrium rotational constant at the minimum, k is the harmonic force constant, α is the spin-rotation constant, and κ is the reduced curvature value. b CASSCF+MRCI calculations from ref . c CI calculations from ref . …”

“…4À10 (This comment applies to all-electron calculations, and those where "small-core" effective core potentials have been used; often the latter have necessitated augmentation of standard basis sets with tight basis functions to describe the outer-core/valence correlation.) Spectroscopic parameters have been determined from these potentials and are compared to the only previous reports of calculations on the Ga þ ÀRG and In þ ÀRG complexes: configuration interaction (CI) calculations by Dunning et al 15 for Ga þ ÀAr and the results of a more recent CASSCF and MRCI study of Ga þ ÀAr by Park et al 16 In addition, we shall compare the spectroscopic parameters we obtain for Ga þ ÀRG to those obtained experimentally for excited states of GaÀRG obtained by Stangassinger et al, 17 and our previously calculated results for the Tl þ ÀRG complexes will be compared to those obtained, again experimentally, for the excited states of TlÀRG. 18 Finally, we shall discuss trends in the values of the spectroscopic quantities in group 13 and present results on the transport coefficients.…”