Formyl chloride: UV absorption cross sections and rate constants for the reactions with chlorine atom and hydroxyl radical

Ab initio MRD-CI study of excited states of formyl chloride HClCO and photofragmentation along Cl–C cleavage

“…3a 00 is the HOMO-LUMO transition, computed at 5.04 eV. This is in reasonable agreement with the experimental value of 4.76 eV reported by both Libuda et al [18] and Judge and Moule [61]. QCISD(T) calculations of the vertical excitation energy of formyl chloride by Bent and co-workers [51] resulted in 4.81 eV, while the same authors obtained 4.71 eV with density functional calculations.…”

“…Several theoretical and experimental studies examine the kinetic and photochemical behavior of formyl chloride. Libuda et al [18] measured the UV absorption cross sections and rate constants for the reactions of formyl chloride with Cl and OH. Anand and Schlegel [19] studied the unimolecular dissociation of formyl halides (X = F, Cl) by an ab initio direct classical trajectory study.…”

Quantum chemistry and density functional calculations of formyl chloride

“…Projecting out the unwanted spin contamination improves the AE value. As more correlation energy and less spin contamination are included in the method, the vertical excitation energy approaches the experimental value [1] until with the QCISD(T) method the agreement is excellent. It is extremely difficult to calculate the spin contamination in a UST4CCD or UQCISD(T) wavefunction, and this quantity is not calculated in the Gaussian programs.…”

“…One possible mechanism for its destruction in the troposphere is photodissociation. Libuda et al [1] have recently measured the near-ultraviolet absorption coefficients of HC1CO. They identified the absorption maximum at 260'2 nm (4.79 eV) which sets a lower limit of 50 days for the photolytic lifetime of HC1CO in the troposphere.…”

“…However, the r(CC1) bond length determined with DMol agrees much better with experiment than the Gaussian 90 calculation. Table 2 shows the vertical excitation energies calculated with the methods in the Gaussian programs and DMol compared with the recent experimental value determined by Libuda et al [1]. The ground state energy from DMol was included in table 2 for completeness, but it should not be compared with the Gaussian method energies since Kohn-Sham orbitals are used in the density functional calculations while HF orbitals are used in the Gaussian calculations.…”