Cluster-ion formation in pulsed-laser-stimulated field desorption of condensed materials

1985 ◽  
Vol 32 (7) ◽  
pp. 4340-4357 ◽  
Author(s):  
T. T. Tsong ◽  
Y. Liou
Keyword(s):  
Pulsed Laser ◽  
Field Desorption ◽  
Ion Formation ◽  
Cluster Ion ◽  
Condensed Materials

Comparison of Laser (LMS), Californium-252 Plasma Desorption (252Cf-PDMS), Fast Atom Bombardment (FAB), Secondary Ion (SIMS), and Field Desorption (FD) Mass Spectra of a Series of Internal Salts

1987 ◽  
Vol 41 (5) ◽  
pp. 821-829 ◽  
Author(s):  
Kesagapillai Balasanmugam ◽  
Somayajula Kasi Viswanadham ◽  
David M. Hercules ◽  
Robert J. Cotter ◽  
David Heller ◽  
...  
Keyword(s):  
Structure Elucidation ◽  
Mass Spectra ◽  
Fast Atom Bombardment ◽  
Negative Ion ◽  
Cluster Ions ◽  
Field Desorption ◽  
Ion Formation ◽  
Plasma Desorption ◽  
Cluster Ion ◽  
Secondary Ion

Comparison of the mass spectral techniques of Laser (LMS), Californium-252 Plasma Desorption (252Cf-PDMS), Secondary Ion (SIMS), Fast Atom Bombardment (FAB), and Field Desorption (FD) Mass Spectrometry is presented for the positive- and negative-ion spectra of a series of internal salts (zwitterions) known as the sultaines. The spectral characteristics compared are: quasimolecular ions, fragment ions and their implication for structure determination, and cluster-ion formation. Quasimolecular ions corresponding to (M + H)+ (all techniques); (M+CH3)+ (LMS, PDMS, SIMS); (M+R)+ (R = long alkyl chain up to C12, LMS); (M+Na)+ (SIMS, 252Cf–PD); (M+Ag)+ (SIMS), (M–H)− (FAB); (M–CH3)−; and (M–R) were observed (negative-ion FD mass spectra were not obtained). Extensive fragmentation is observed for PDMS and LMS, providing the highest level of structural information. Also, the possibilities for structure elucidation by SIMS are very good. Minimal fragmentation is observed for FAB; however, complete structure elucidation is possible by using both the positive- and negative-ion FAB spectra. FD is a less favored technique for the structural analysis of the sultaines. The negative-ion spectra of sultaines obtained by LMS, PDMS, SIMS, and FAB showed identical peaks in the lower mass ranges ( m/z < (M–CH3)−), although of varying intensities. Cluster ions and solvated (glycerol) cluster ions are observed in negative FAB in the higher mass ranges ( m/z > (M–CH3)−). FAB is unique with respect to cluster-ion formation; cluster ions of high order [( nM + H)+, n = 2–14; ( nM?CH3)−, ( nM–R)−, n = 2–9; ( lM+ mG–H)−, l = 1–4, m = 1–3] are observed. Other techniques show cluster ions such as ( nM+H)+, n = 2–3 (SIMS, PDMS, FD); ( nM+Na)+, n = 2 (SIMS and PDMS); and (2M+Ag)+ (SIMS). No cluster ions were observed in LMS.

Ion Formation from Alkali Iodide Solids by Swift Dust Particle Impact

1982 ◽  
Vol 37 (12) ◽  
pp. 1335-1340 ◽  
Author(s):  
W. Knabe ◽  
F. R. Krueger
Keyword(s):  
Thermal Effects ◽  
Pulsed Laser ◽  
Dust Particles ◽  
Metal Foils ◽  
Ion Formation ◽  
Flight Mass Spectrometry ◽  
Coated Metal ◽  
The Impact ◽  
Pulsed Laser Irradiation

AbstractSwift Fe-dust particles (0.2-20 μmØ ; 1-50 km/s) are utilized to generate transiently ions from alkali iodide coated metal foils, analyzed by time-of-flight mass spectrometry. By means of a thermodynamic treatment it is shown that simple heating by the impact cannot be hold responsible for the ion formation. However, this process is very much related to the non-adiabatic ion formation by pulsed laser irradiation. The damage caused by the impact particle resulting in cratering and thermal effects, which are long-term processes, is not related to the instantaneous ion formation.

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