The empirical equilibrium structure of diacetylene

Abstract: High-level quantum-chemical calculations are reported at the MP2 and CCSD(T) levels of theory for the equilibrium structure and the harmonic and anharmonic force fields of diacetylene, Hh name="tbnd" />Ch name="tbnd" />Clculations were performed employing Dunning’s hierarchy of correlation-consistent basis sets cc-pVXZ, cc-pCVXZ, and cc-pwCVXZ, as well as the ANO2 basis set of Almlöf and Taylor. An empirical equilibrium structure based on experimental rotational constants for 13 isotopic species of diacetylene and computed zero-point vibrational corrections is determined and in good agreement with the best theoretical structure (CCSD(T)/cc-pCV5Z: , , ). In addition, the computed fundamental vibrational frequencies are compared with the available experimental data and found in satisfactory agreement. [Copyright &y& Elsevier]