Formation of H3O+ from alcohols and ethers induced by intense laser fields.
The processes of H(3)O(+) production from alcohols (ethanol, 2-propanol, 1-propanol, 2-butanol) and ethers (diethyl ether and ethyl methyl ether), and their deuterium-substituted species, by intense laser fields (800 nm, 100 fs, approximately 1 x 10(14) W/cm) were investigated through time-of-flight (TOF) mass spectrometry. H(3)O(+) formation was observed for all these compounds except for ethyl methyl ether. From the analysis of TOF signals of H((3-n))D(n)O(+) (n = 0, 1, 2, and 3) that have expanding tails with increasing flight time, it has been confirmed that the reaction proceeds through metastable dissociation from the intermediate species C(2)H((5-m))D(m)O(+)(m = 0-5). The common shape of the H((3-n))D(n)O(+) signal profiles contains two major distributions in the time constant, i.e., fast and slow components of <50 ns and approximately 500 ns, respectively. The H((3-n))D(n)O(+) branching ratio is interpreted to be the result of complete scrambling of four hydrogen atoms at the C-C site in C(2)H(4)-OH(+), and partial exchange (18-38%) of a hydrogen atom in the OH group with four other hydrogen atoms within 1 ns prior to H((3-n))D(n)O(+) production. Ab initio calculations for the isomers and transition states of C(2)H(5)O(+) were also performed, and the observed H((3-n))D(n)O(+) production mechanism has been discussed. In addition, a stable isomer having a complex structure and two isomerization pathways were discovered to contribute to the H(3)O(+) formation process.
Shirota
Tatsuro
T
Department of Pharmacy, Niigata University of Pharmacy and Applied Life Sciences, 265-1 Higashijima, Akiha-ku, Niigata City 956-8603, Japan.
Mano
Narutoshi
N
Tsuge
Masashi
M
Hoshina
Kennosuke
K
D019840:2-Propanol / Q000737:chemistry*; D003903:Deuterium / Q000737:chemistry; D041961:Deuterium Exchange Measurement / Q000379:methods; D004987:Ethers / Q000737:chemistry*; D007536:Isomerism; D007834:Lasers; D009861:Onium Compounds / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods
D004987:Ethers; D009861:Onium Compounds; C027727:hydronium ion; D003903:Deuterium; D019840:2-Propanol