Femtosecond laser interactions with methyl iodide clusters. I. Coulomb explosion at 795 nm

Abstract

The study of the interaction of femtosecond laser radiation with matter, especially clusters, has blossomed in recent years due to advances in laser technology. One aspect of this interaction is Coulomb explosion. This effect occurs when the repulsive energy of like charges, known as Coulomb repulsion, overcomes the cluster’s total cohesive energy, causing the cluster to disintegrate into charged fragments. In this study, the interactions of methyl iodide clusters, formed in a supersonic expansion using argon and helium as carrier gases, were investigated at 795 nm using a Ti:Sapphire femtosecond laser. The resulting atomic and cluster ions were analyzed in a reflection time-of-flight mass spectrometer. The focus of these studies was the elucidation of the effects of carrier gas and laser wavelength on the laser-cluster interactions leading to Coulomb explosion. To achieve these goals, the effects of different carrier gases, laser power, cluster distribution, and the resulting Coulomb explosion energies were examined. A secondary consideration was to examine the experimental results with regard to the Coherent Electron Motion and Ionization Ignition models.

Explosions of water clusters in intense laser fields

“…Relatively little work has been reported on the interaction of intense laser light with molecular clusters [13,14,22] and it has relied exclusively on the application of onedimensional TOF methodology to clusters of modest size. The application of 2D-TOF methodology to atomic [2,19] and molecular clusters opens new vistas for such research; as the present results indicate, it also questions prevailing wisdom regarding cluster explosion dynamics.…”

Multiple ionization of CH3I clusters by nanosecond laser: Electron energy distribution and formation mechanism of multiply charged ions

“…Recently, the interaction of nanosecond laser with CH 3 I cluster was investigated widely, where multiply charged ions with high energy were observed experimentally [4][5][6][7]. Luo et al investigated the interaction of nanosecond laser with CH 3 I in diffused beam and pulsed beam by a time-of-flight mass spectrometer [8].…”

Cluster-assistant generation of multiply charged atomic ions in nanosecond laser ionization of seeded methyl iodide beam

“…Methyl iodide (CH 3 I) has been chosen in this experiment as it has been extensively studied in the past and is still the subject of many studies in recent years [18][19][20][21][22][23][24][25][26][27][28][29][30]. Recently, Graham et al [25] reported the study of the multielectron dissociative ionization (MEDI) processes induced by 50 fs strong laser at 10 16 W/cm 2 .…”

“…Lots of works about traditional MPI have been done under a laser intensity of 10 6 -10 9 W/cm 2 [19,21], and recent works about high intensity laser field and molecules were done under a laser intensity of 10 13 -10 17 W/cm 2 by picosecond and femtosecond lasers [25][26][27][28][29][30]. Recently, we reported the generation of C q+ (q = 2,3) in photoionization of benzene seeded in argon by 25 ns, 532 nm pulses from a YAG laser at intensity about 10 11 W/cm 2 [31].…”