A portion of I2 spectra acquired in the photolysis of CH2I2 at 248 nm. (a) The band for v = 0 and 1 contained in the region of 514.5–515 nm. (b) The band for v = 0, 1, and 2 contained in the region of 519–519.5 nm. (a) denotes trace acquired experimentally, while (b) is a simulated spectrum.
(a) I2 spectra acquired in the 248 nm photolysis of CH2I2 at pressure of 120 mTorr; (b) trace acquired in the 248 nm photolysis of CH3I at pressure of 500 mTorr.
Laser energy dependence of I2 fragment intensity at 514.537 nm contributed mainly from rotational line R(109) of the (50,0) band.
I2 fragment intensity as a function of CH2I2 pressure varied from35 to 125 mTorr.
(a) Comparison between observed (dashed line) and simulated spectra (solid line) of I2 in which the v = 1/v = 0 vibrational population ratio is optimized to 0.65 ± 0.10. (b) A portion of simulated spectra of I2 with different v = 2/v = 0 vibrational population ratios. (c) Comparison between observed and simulated spectra in which the v = 2/v = 0 population ratio is optimized to 0.30 ± 0.05, as the v = 1/v = 0 ratio is fixed at 0.65.
The dissociation channels initiated from the ground state potential energy surface of CH2I2, in which the energies in kJ/mol relative to CH2I2 are computed with CCSD(T)/midix level of theory with B3LYP/midix zero-point energy corrections at B3LYP/midix optimized geometries.
Some structures along the dissociation pathways of CH2I2.
Temperature dependence of the line intensity of I2 at 514.537 nm in the photodissociation at 248 nm.
Density of vibrational states of CH2I2 and CH2Br2 as a function of excitation energy.
The calculated energies of the unrestricted B3LYP/midix optimized geometries for the I2 dissociation channels on the adiabatic singlet ground state potential energy surface of CH2I2.
RRKM rate constants (s−1) computed with B3LYP/midix zero-point energy corrected CCSD(T)/midix energies and B3LYP/midix harmonic frequencies for reactions paths on the adiabatic singlet ground state surface of CH2I2 at 248 nm.
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