title: Structure, Reactivity, and Fragmentation of Small Multi-Charged Methane Clusters.
abstract: Small methane clusters (CH4)n are irradiated using intense femtosecond laser excitation at 624 nm. The ionized species and those resulting from their fragmentation are detected via time-of-flight mass spectrometry (TOF MS). We find evidence of bound, multiply charged methane molecules and clusters resulting from Coulomb explosion upon exposure to highly energetic, ultrafast radiation. The assignment of the mass spectra is done after first-principles calculations (at the (R)MP2/aug-cc-pVXZ (X = D,T) level) on the charged (CH4)n(q+) clusters (n = 1-4, q = 1-4). We also considered the cluster stabilities and fragments that may result from intracluster molecular reactivity. Complex intracluster ion-molecule reactions induced by photoionization are expected to occur. Interestingly, we show that multi charged small methane clusters undergo intracluster reactions and fragmentations which are different from those observed for isolated methane ions or for large ionized methane clusters.
authors.affiliation: Laboratoire de Spectroscopie Atomique, Moléculaire et Applications - LSAMA, Université de Tunis Al Manar , Tunis, Tunisia.
authors.forename: A Sanaa
authors.initials: AS
authors.lastname: Zaag
authors.affiliation: Laboratoire de Spectroscopie Atomique, Moléculaire et Applications - LSAMA, Université de Tunis Al Manar , Tunis, Tunisia.
authors.forename: O
authors.initials: O
authors.lastname: Yazidi
authors.affiliation: Laboratoire de Spectroscopie Atomique, Moléculaire et Applications - LSAMA, Université de Tunis Al Manar , Tunis, Tunisia.
authors.forename: N-E
authors.initials: NE
authors.lastname: Jaidane
authors.affiliation: Departments of Chemistry and Physics, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors.forename: M W
authors.initials: MW
authors.lastname: Ross
authors.affiliation: Departments of Chemistry and Physics, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.
authors.forename: A W
authors.initials: AW
authors.lastname: Castleman
authors.affiliation: Chemistry Department, Faculty of Science, King Saud University , P.O. Box 2455, Riyadh 11451, Kingdom of Saudi Arabia.
authors.forename: M M
authors.initials: MM
authors.lastname: Al Mogren
authors.affiliation: Laboratoire Modélisation et Simulation Multi-Echelle, MSME UMR 8208 CNRS, Université Paris-Est , 5 bd Descartes, 77454 Marne-la-Vallée, France.
authors.forename: R
authors.initials: R
authors.lastname: Linguerri
authors.affiliation: Laboratoire Modélisation et Simulation Multi-Echelle, MSME UMR 8208 CNRS, Université Paris-Est , 5 bd Descartes, 77454 Marne-la-Vallée, France.
authors.forename: M
authors.initials: M
authors.lastname: Hochlaf