Resonance multiphoton ionization and dissociation of dimethyl ether via the and states

Abstract

The three-photon resonance four-photon ionization and dissociation spectra of dimethyl ether (DME) are presented in the wavelength range 450–550 nm at 1 nm intervals. The (3+1) REMPI spectra show three prominent bands corresponding to the and transitions with origins at 61 457 cm−1 (7.615 eV), 59 055 cm−1 (7.322 eV) and 58 010 cm−1 (7.194 eV), respectively. Several ionized species, CH3+, CHnO+ (n = 1–3) and CH3OCH3+, are observed in the region of wavelengths studied here. In order to compare the results, a shorter wavelength multiphoton dissociation and ionization of DME at 355 nm is also presented. At this wavelength, DME undergoes neutral dissociation to CH3 and CH3O and each fragment is then ionized by multiphoton absorption. The fragmentation at 355 nm is very intense and only small fragments such as CH3+, CHO+, CH2+, CH+ and C+ ions are observed. The measurement of photoelectron energy allows us to establish that the DME ionization potential is at least 9.55 ± 0.15 eV. The experiments were performed using a Nd:YAG-OPO (optical parametric oscillator) tunable laser system coupled to a time-of-flight mass spectrometer and a hemispherical electron energy analyser.

Multiply ionization of diethyl ether clusters by 532nm nanosecond laser: The influence of laser intensity and the electron energy distribution

“…2, it can be seen that multiply charged ions of C q+ (q = 2-4) and O q+ (q = 2-4) were observed and some fragment ions of diethyl ether such as C 2 H þ 5 , CH 3 O + , C 2 H 5 O + and C 4 H 9 O + were also recorded. The formation of fragment ions of diethyl ether from MPI has been discussed previously [13][14][15]. In this text, only the formation mechanisms of multiply charged ions of C q+ (q = 2-4) and O q+ (q = 2-4) are investigated and discussed in details.…”

“…Dimethyl and diethyl ether are typical organic molecules to investigate the ionization and dissociation dynamics [13][14][15]. For example, Zhu et al [13] investigated the fragmentation of dimethyl ether (DME) in intense femtosecond laser field 810, 405 and 270 nm and proposed there were different dissociation channel at different wavelength.…”

“…Wei et al [14] investigated the multiphoton ionization of ether clusters to illustrate the intracluster ion-molecular reactions and metastable decompositions [14]. Mejia-Ospino et al [15] measured the kinetic energy of the ejected electrons to understand (3 + 1) REMPI of dimethyl ether. However, the multiply ionization of ether clusters with intense laser has not been published.…”

FTIR Analysis of Dimethyl Ether Decomposition Products Following Charge Transfer Ionization with Ar+ under Matrix Isolation Conditions

“…Dimethyl ether (CH 3 OCH 3 ) is the simplest molecule containing the ether functional group, and as a result, understanding the chemistry of this species is useful for building an understanding of the chemistry of larger homologous ether molecules. Additionally, the decomposition chemistry of cationic dimethyl ether has been well characterized by various ionization and mass spectrometric techniques − and with complementary theory investigating decomposition. − Comparison with such analyses allows us to further evaluate our electron bombardment matrix isolation infrared studies as a complementary technique to decomposition chemistry observed through mass spectrometric analysis.…”