Photochemistry of diethyl ether clusters at 1012 W/cm2: A mass spectrometry and charge density study

Abstract

Photochemistry of diethyl ether clusters has been studied at discrete laser wavelengths spanning from UV to IR region at intensity ~1012 W/cm2 using time-of-flight mass spectrometry. At 266 nm, singly charged fragments, protonated cluster ions were observed due to multiphoton ionisation of clusters. Further, intra cluster ion–molecule reactions lead to generation of H2+, H3+ ions. In addition, C2+ ions were observed at this wavelength. With increase in laser wavelength to 355, 532 and 1064 nm, systematic increase in charge state of multiply charged atomic ions of oxygen, carbon was observed. Highest observed charge states were O6+, C4+ at 1064 nm. Mass spectrometric study was complemented by charge density measurement, which shows an increasing trend with wavelength supporting efficient ionisation of clusters at longer wavelength. Studies reveal that ionisation is initiated via multiphoton ionisation followed by electron ionisation. The multiple ionisation of diethyl ether clusters predominantly depends on the rate of energisation of electrons in the laser field and Coulomb stability of the cluster has insignificant contribution to the final ionic outcome.