Phosgene at the complete basis set limit of CCSDT(Q): Molecular structure and rovibrational analysis

Abstract

The ground-state (X∼1A″) equilibrium geometry of phosgene is examined with coupled-cluster theory, using derivatives extrapolated to the complete basis set (CBS) limit of CCSDT(Q). The C–O and C–Cl bond lengths are predicted to be 1.1768Å and 1.7374Å, respectively; the Cl–C–Cl bond angle is 124.03° and the O–C–Cl bond angle is 111.93°. Anharmonic frequencies are determined with VPT2, using CCSD(T)/cc-pCVQZ cubic and quartic force-fields and a CCSDT(Q)/CBS quadratic force field: ν1=1832.9; ν2=570.5; ν3=301.2; ν4=576.3; ν5=849.4; and ν6=438.9cm−1.