As a kind of toxic methylation reagent and disinfectant, methyl iodide (CH3I) is widely used. It is important to study the basic physical properties of methyl iodide and to use effective measures to degrade it. The ground states of methyl iodide in different electric fields from 0 to 0.04a.u.(atomic unit) are optimized using the B3LYP calculation with the LANL2DZ basis set. Optimized parameters, total energies, bond lengths, dipole moments, the highest occupied molecular orbital energies, the lowest unoccupied molecular orbital energies, energy gaps, infrared spectra, and dissociation potential energy surface (PES) are obtained. The obtained results show that when the external electric field gradually increases from 0 to 0.04a.u. along the molecular axis Z (the C-I bond direction), the total energy decreases while the dipole moment increases. The C-I and C-H bond lengths increase gradually. The energy gap first increases and then decreases with the external electric field. Further studies show that when the external electric field increases from 0 to 0.04 a.u., the dissociation PES along the C-I bond becomes unbound with the potential energy barrier disappearing. The external electric field of 0.04 a.u. is sufficient to induce the degradation of methyl iodide with the C-I bond breaking. This work provides an important support for the degradation of methyl iodide in the external electric field.
ZHANG Xiangyun
,
LIU Yuzhu
,
MA Xinyu
,
QIN Chaochao
. Dissociation and physical properties of methyl iodide in external electric field[J]. Journal of University of Chinese Academy of Sciences, 2018
, 35(6)
: 839
-844
.
DOI: 10.7523/j.issn.2095-6134.2018.06.016
[1] Schwartz M D, Obamwonyi A O, Thomas J D, et al. Acute methyl iodide exposure with delayed neuropsychiatric sequelae:report of a case[J]. Am J Ind Med, 2005, 47(6):550-556.
[2] Nair J R, Chatteriee K. Methyl iodide poisoning presenting as a mimic of acute stroke:a case report[J]. J Med Case Rep, 2010, 4(1):1-4.
[3] Liu Y Z, Thomas G, Gregor K. Optical control of the vibrational excitation of the polyatomic ions via strong field multi-photon ionization[J]. Acta Phys Sin, 2014, 63(24):244208(in Chinese).
[4] Schiermeier Q. Chemists poke holes in ozone theory[J]. Nature, 2007, 449(7161):382-383.
[5] Hobe M V. Revisiting ozone depletion[J]. Science, 2007, 318(5858):1878-1879.
[6] Liu Y Z, Long J Y, Zhang X Y, et al. Probing ultrafast dissociation dynamics of chloroiodomethane in the B band by time-resolved mass spectrometry[J]. Chinese Phys Lett, 2017, 34(3):033301.
[7] Liu Y Z, Gerber T, Radi P, et al. Switching the vibrational excitation of a polyatomic ion in multi-photon strong field ionization[J]. Chemical Physics Letters, 2014, 610-611:153-158.
[8] Li X X, Zhang Z P, Long Z W, et al. Ground state properties and spectral properties of borospherene B40 under different external electric fields[J]. Acta Phys Sin, 2017, 66(10):103102(in Chinese).
[9] Wu Y G, Li S X, Hao J X, et al. Properties of ground state and spectrum of CdSe in different external electric gelds[J]. Acta Phys Sin, 2015, 64(15):153102(in Chinese).
[10] Bhattachryya P K. Effect of external electric field on ground and singlet excited states of phenylalanine:a theoretical study[J]. Computational and Theoretical Chemistry, 2015, 1057:43-53.
[11] Shen H J, Shi Y J. Geometey configuration and invalidity of Dimer C60 fullerene molecule in applied external electric field[J]. Chin J Chem Phys, 2005, 18(3):351-356(in Chinese).
[12] Zhang G Q, Xie S J. Temperature and electric field effect on proton transfer in adenine-thymine[J]. Bull Korean Chem Soc, 2014, 35(12):3532-3534.
[13] Frish M J, Trucks G W, Schlegel H B, et al. Gaussian 09,Revision C.01[CP]. Walling ford:Gaussian Inc, 2010.
[14] Kjellberg P, He Z, Pullerits P. Bacteriochlorophyll in electric field[J]. J Phys Chem B, 2003, 107(49):13737-13742.
[15] Grozema F C, Telesca R, Jonkman H T, et al. Excited state polarizabilities of conjugated molecules calculated using time dependent density functional theory[J]. J Chem Phys, 2001, 115(21):10014-10021.
[16] Sutton L E. Tables of molecular parameters-carbon compounds[EB/OL]. (1958)[2017-07-18]. http://www.wiredchemist.com/chemistry/data/carbon-compounds.
[17] Shimanouchi T. "Vibrational and/or electronic energy levels" in NIST Chemistry WebBook[EB/OL].(1968-07-11)[2017-07-18].http://webbook.nist.gov/cgi/cbook.cgi?ID=C74884&Units=SI&Mask=800#Electronic-Spec.
