Using a homemade time-of-flight mass spectrometer, the ionization and dissociation of gaseous molecular allyl bromide in 800 nm and 400 nm femtosecond laser fields were studied. By analyzing the dependence of ion fragment yields and laser intensity, combined with calculation of the Keldysh parameter, it was shown that multi-photon ionization dominates the ionization process involved in our experiment. Based on a theoretical calculation with the Gaussian 09 software package, flexible force constants and appearance energies of different fragment ions were calculated and dissociation channels were identified. Meanwhile, the results demonstrate that non-resonant multi-photon absorption will lead to simultaneous cleavage of multi-chemical bonds; moreover, the charge distribution of parent ions will steer the reaction pathway.
LIU Yang
,
LIU Bo-tong
,
YANG Yan
,
SUN Zhen-rong
. Dissociative ionization of allyl bromide in 800 nm and 400 nm intense femtosecond laser fields[J]. Journal of East China Normal University(Natural Science), 2019
, 2019(3)
: 110
-119
.
DOI: 10.3969/j.issn.1000-5641.2019.03.012
[1] GOUGOUSI T, SAMARTZIS P C, KITSOPOULOS T N. Photodissociation study of CH3Br in the first continuum[J]. The Journal of Chemical Physics, 1998, 108(14):5742-5746.
[2] MAO R, ZHANG Q, ZANG J Z, et al. Multiphoton dissociative ionization of tert-pentyl bromide near 265 nm[J]. The Journal of Chemical Physics, 2011, 135(24):244302.
[3] GARDINER S H, KARSILI T N, LIPCIUC M L, et al. Fragmentation dynamics of the ethyl bromide and ethyl iodide cations:A velocity-map imaging study[J]. Physical Chemistry Chemical Physics, 2014, 16(5):2167-2178.
[4] PRATHER M J, WATSON R T. Stratospheric ozone depletion and future levels of atmospheric chlorine and bromine[J]. Nature, 1990, 344:729-734.
[5] MORGON N H, GIROLDO T, LINNERT H V, et al, Isomerization of the molecular ion of allyl bromide[J]. The Journal of Physical Chemistry, 1996, 100(46):18048-18056.
[6] PARK M S, LEE K W, JUNG K H, Br and Cl atom formation dynamics of allyl bromide and chloride at 234 nm[J]. The Journal of Chemical Physics, 2001, 114(23):10368-10374.
[7] PANDIT S, PRESTON T J, KING S J, et al. Evidence for concerted ring opening and C-Br bond breaking in UV-excited bromo cyclopropane[J]. The Journal of Chemical Physics, 2016, 144:244312.
[8] OHTA K, ANTONOV L, YAMADA S, et al. Theoretical study of the two-photon absorption properties of several asymmetrically substituted stilbenoid molecules[J]. The Journal of Chemical Physics, 2007, 127(8):084504.
[9] WU C Y, XIONG Y J, JI N, et al. Field ionization of aliphatic ketones by intense femtosecond laser[J]. The Journal of Physical Chemistry A, 2001, 105(2):374-377.
[10] CORNAGGIA C, SCHMIDT M, NORMAND D. Coulomb explosion of CO2 in an intense femtosecond laser field[J]. Journal of Physics B:Atomic, Molecular and Optical Physics, 1994, 27(7):123-130.
[11] BRANDHORST K, GRUNENBERG J. Efficient computation of compliance matrices in redundant internal coordinates from Cartesian Hessians for nonstationary points[J]. The Journal of Chemical Physics, 2010, 132:184101.
[12] BRANDHORST K, GRUNENBERG J. How strong is it? The interpretation of force and compliance constants as bond strength descriptors[J]. Chemical Society Reviews, 2008, 37(8):1558-1567.
[13] HEHRE W J, STEWART R F, POPLE J A. Self-consistent molecular orbital methods. 1. use of Gaussian expansions of Slater-type atomic orbitals[J]. The Journal of Chemical Physics, 1969, 51:2657-2664.
[14] FELDMANN D, PETRING D, OTTO G, et al. Angular distribution of photo electrons from above-thresholdionization (ATI) of xenon by 532 nm, 355 nm and 266 nm radiation[J]. Zeitschrift für Physik D Atoms, Molecules and Clusters, 1987, 6(1):35-42.
[15] KAWATA I, KONO H, FUJIMURA Y. Adiabatic and diabatic responses of H+2 to an intense femtosecond laser pulse:Dynamics of the electronic and nuclear wave packet[J]. The Journal of Chemical Physics, 1999, 110(23):11152-11165.
[16] KELDYSH L V. Ionization in the field of a strong electromagnetic wave[J]. Journal of Experimental and Theoretical Physics, 1964, 47, 1945-1957.
[17] GUO C M, LI M D, NIBARGER J P, et al. Single and double ionization of diatomic molecules in strong laser fields[J]. Physical Review A, 1998, 58(6):4271-4274.
[18] SOBEREVA.通过柔性力常数考察键的强度[OB/OL]. (2017-03-01)[2018-03-03]. http://sobereva.com/364.
[19] REED A E, WEINSTOCK R B, WEINHOLD F. Natural population analysis[J]. The American Institute of Physics, 1985, 83(2):735-746.