CH2BrI Research Articles

Fourier transform microwave and millimeter-wave spectroscopy of bromoiodomethane, CH2BrI.

Bromoiodomethane, CH2BrI, is a molecule of natural origin emitted in significant amount into the marine boundary layer. It can easily be decomposed by solar radiation, releasing Br and I atoms in the troposphere, which in turn impacts the atmospheric chemistry. Spectroscopy is an invaluable tool to monitor species present in the atmosphere. Since no high-resolution spectroscopic studies are available for this dihalomethane, we have investigated the rotational spectra of the two bromine isotopologues of CH2BrI in its vibrational ground state in the microwave and millimeter-wave regions. Transitions of b-type have been recorded by Fourier transform microwave spectroscopy below 25 GHz while both a- and b-type spectral lines have been measured below 230 GHz. Observed transitions correspond to energy levels with J ≤ 132 and Ka ≤ 14. Molecular constants including those describing the nuclear quadrupole coupling tensors for (79)Br, (81)Br, and (127)I were accurately determined from the least-squares analysis of a total of 1873 distinct transition frequencies (of which 943 belong to the CH2(79)BrI isotopologue). An experimental (r0) structure of the title species has been derived from the two sets of rotational constants.

Picosecond time-resolved resonance Raman observation of Iso-CH 2Br–I following A-band photodissociation of CH 2BrI in the solution phase

We present picosecond time-resolved resonance Raman spectra that demonstrate formation of the iso-CH 2Br–I species following A-band excitation of bromoiodomethane in cyclohexane solvent at room temperature. The iso-CH 2Br–I species is produced within several ps and appears to decay with a half-life on the 2–3 ns time scale. We compare these results to previous studies on solution phase photodissociation of dihalomethanes.

Photodissociation of a molecule with two chromophores. Bromoiodomethane

Photodissociation of a molecule with two chromophores. Bromoiodomethane