The ionization of acetylene molecules is an important process for many different fields, such as, for instance, plasma devices, flames, planetary atmospheric chemistry and semiconductor industry. The two-body dissociation reactions of the dication, C2H22+, produced by 39.0 eV double photoionization of acetylene molecules, have been studied by coupling photoelectron-photoion-photoion coincidence and ion imaging techniques. The ion image analysis provides the angular distribution of product ions with respect the polarization vector direction. It is well known that such angular distributions can support valuable information about the dissociation dynamics. The obtained results provide the kinetic energy and the angular distributions of product ions, being the angle defined with respect the linear polarization vector of the ionizing light. The analysis of these results indicates that the dissociation leading to C2H++H+ products occurs through a metastable dication with a lifetime of 108±22 ns, and the kinetic energy release (KER) distribution exhibits a maximum at 4.3 eV with a full width at half maximum (FWHM) of about 60%. The reaction leading to CH2++C+ occurs in time shorter than the typical rotational period of the acetylene molecules (of the order of 10-12 s). The KER distribution of product ions, for this reaction, exhibits a maximum at 4.7 eV with a FWHM of about 28%. The symmetric dissociation, leading to CH++CH+, exhibits a KER distribution with a maximum at 5.2 eV with a FWHM of 44%.

Dissociative double photoionization dynamics of acetylene molecules by linearly polarized light

CANDORI, Pietro;FALCINELLI, Stefano;PIRANI, Fernando;VECCHIOCATTIVI, Franco
2012

Abstract

The ionization of acetylene molecules is an important process for many different fields, such as, for instance, plasma devices, flames, planetary atmospheric chemistry and semiconductor industry. The two-body dissociation reactions of the dication, C2H22+, produced by 39.0 eV double photoionization of acetylene molecules, have been studied by coupling photoelectron-photoion-photoion coincidence and ion imaging techniques. The ion image analysis provides the angular distribution of product ions with respect the polarization vector direction. It is well known that such angular distributions can support valuable information about the dissociation dynamics. The obtained results provide the kinetic energy and the angular distributions of product ions, being the angle defined with respect the linear polarization vector of the ionizing light. The analysis of these results indicates that the dissociation leading to C2H++H+ products occurs through a metastable dication with a lifetime of 108±22 ns, and the kinetic energy release (KER) distribution exhibits a maximum at 4.3 eV with a full width at half maximum (FWHM) of about 60%. The reaction leading to CH2++C+ occurs in time shorter than the typical rotational period of the acetylene molecules (of the order of 10-12 s). The KER distribution of product ions, for this reaction, exhibits a maximum at 4.7 eV with a FWHM of about 28%. The symmetric dissociation, leading to CH++CH+, exhibits a KER distribution with a maximum at 5.2 eV with a FWHM of 44%.
2012
9781849734486
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11391/1002266
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