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RESEARCH PRODUCT

The semi-experimental equilibrium structures of AlCCH and AlNC

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Abstract Based on experimental rotational constants available in the literature (Walker and Gerry, Chem. Phys. Lett. 278, 9 (1997); Walker et al., J. Mol. Spectrosc. 209, 178 (2001); Sun et al., Chem. Phys. Lett. 553, 11 (2012)) [14,17,19] for five isotopologues of AlCCH and three isotopologues of AlNC as well as quantum-chemical computations for the vibrational corrections to rotational constants, the semi-experimental structures of these two aluminum compounds are determined. These empirical equilibrium structures (AlCCH: r e (Al C) = 1.957 A, r e (C C) = 1.222 A, r e (C H) = 1.065 A; AlNC: r e (Al N) = 1.850 A, r e (N C) = 1.181 A) compare favorably with theoretical best-estimate structures obtained using highly accurate coupled-cluster calculations in combination with sophisticated extrapolation and additivity schemes, i.e., the deviations are smaller than 0.002 A, but significant deviations are noted in comparison with previously determined experimental structures. Good agreement is also reached between calculations and experimental values for the relevant spectroscopic parameters of AlCCH and AlNC, indicating the predictive power of state-of-the-art high-level quantum-chemical calculations.