SINGLET-TRIPLET GAP IN HCI HALOCARBENE

The singlet-triplet energy separation, geometrical structure, harmonic vibrational frequencies, adiabatic ionization potential and electron affinity, dissociation energies and dipole moment for HCI have been determined by using the linear combination of Gaussian-type orbital-local spin density method (LCGTO-LSD) and employing both the local and nonlocal exchange and correlation potentials. Computations show that HCI has a singlet ground state (1A1) in agreement with a previous theoretical result but in disagreement with recent experimental data. The singlet-triplet energy splitting is found to be 3.7 kcal/mol at the nonlocal level of computation. The calculated spectroscopic parameters agree with experimental ones where available.