Secondary ion mass spectrometry of metal halides. 3. Ionic radii effects in alkali halide clusters

Barlak, T. M.; Campana, Joseph E.; Wyatt, J. R.; Colton, Richard J.

doi:10.1021/j100241a018

Cited by 59 publications

(21 citation statements)

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“…13 The absence of the ion intensity enhancements at n = 6, 12 from the negative ion FAB mass spectra of NEt4X salts and the decrease in the &/I=, ratio on going from NMe4C1 to NMe4Br (Table 4) is consistent with this hypothesis, namely that the formation of stable n = 6, 12 negative cluster ions is favoured when the lattice energy of the NR4X salt is larger. 29 The size of the cation appears to be rather more important in determining the relative stabilities of negative cluster ions than of the corresponding positive species.…”

Section: Effect Of Anion and Cation Sizesupporting

confidence: 57%

“…The 13, and it has been postulated that the stability of the n = 6, 12 cluster ions should increase when the alkali halide lattice energy is larger. 13 The absence of the ion intensity enhancements at n = 6, 12 from the negative ion FAB mass spectra of NEt4X salts and the decrease in the &/I=, ratio on going from NMe4C1 to NMe4Br (Table 4) is consistent with this hypothesis, namely that the formation of stable n = 6, 12 negative cluster ions is favoured when the lattice energy of the NR4X salt is larger.…”

Section: Effect Of Anion and Cation Sizementioning

confidence: 99%

“…[13][14][15][16] In a recent study by Campana and Doyle," enhanced stability for the methene nitramine clusters [(CH,NNO,),H]+ at n = 6, 9, 12, 15 for RDX and at n = 12, 16, 20. . .…”

Section: Introductionmentioning

confidence: 99%

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Studies in cluster ion formation. Part I. Fast atom bombardment mass spectrometry of tetraalkylammonium halides: Factors influencing cluster ion size and stability

Tolun

Todd

1986

Org. Mass Spectrom.

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Positive and negative ion fast atom bombardment mass spectra of tetraalkylammonium halide salts (NKX, where X = C1, Br, I and N K = m e , , NEt.,) have been studied and intense cluster ion formation has been observed. The cluster ion intensity distributions were found to show enhancements at certain cluster numbers (n). The negative cluster ions of NMe,X salts showed anomalous ion intensity regions, which ditfered from both the positive cluster ions of all NKX salts and also the Corresponding negative clusters of NEt,X salts. The iduence of anion and cation sue on cluster ion formation and abundances has been studied and it has been established that smaller anion and cation size favours the formation of larger cluster ions. The possible structures of the cluster ions exhibiting relative increased stabilities are discussed.

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Section: Effect Of Anion and Cation Sizesupporting

confidence: 57%

Section: Effect Of Anion and Cation Sizementioning

confidence: 99%

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Studies in cluster ion formation. Part I. Fast atom bombardment mass spectrometry of tetraalkylammonium halides: Factors influencing cluster ion size and stability

Tolun

Todd

1986

Org. Mass Spectrom.

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“…26 They found that those cluster ions composed of n D 13 and 22 molecules and having regular and compact structures were of greater stability. Barlak et al 23 had proposed 'cubiclike' structures for n D 13 and 22 that can be defined simply as 3 ð 3 ð 3 (corresponding to 13 NaCl molecules plus an ion for a total of 27 ions) and as Tables 1 and 2. 3 ð 3 ð 5 (corresponding to 22 NaCl molecules plus an ion for a total of 45 ions), respectively. However, the enhanced stability of the cluster ions having n D 4 and 9, hence their identification as having magic numbers, is not immediately apparent from the results of Doye and Wales.…”

Section: Results and Discussion Effects Of Instrumental Conditions Anmentioning

confidence: 99%

Electrospray ionization tandem mass spectrometric study of salt cluster ions. Part 1? Investigations of alkali metal chloride and sodium salt cluster ions

et al. 2001

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Salt cluster ions of alkali metal chlorides ACl (A = Li(+), Na(+), K(+), Rb(+) and Cs(+)) and sodium salts NaB (B = I(-), HCOO(-), CH(3)COO(-), NO(2)(-), and NO(3)(-)), formed by electrospray ionization, were studied systematically by mass spectrometry. The influences on the total positive ion and negative ion currents of variation of solvent, solution concentration, desolvation temperature, solution flow-rate, capillary voltage and cone voltage were investigated. Only cone voltage was found to influence dramatically the distribution of salt cluster ions in the mass spectra observed. Under conditions of normal cone voltage of approximately 70 V, cluster ions having magic numbers of molecules are detected with high relative signal intensity. Under conditions of low cone voltage of approximately 10 V, the distribution of cluster ions detected is characterized by a relatively low average mass/charge ratio due to the presence of multiply charged cluster ions; in addition, there is a marked reduction in cluster ions having a magic number of molecules. Product ion mass spectra obtained by tandem mass spectrometry of cluster ions are characterized by a base peak having a magic number of molecules that is less than and closest to the number of molecules in the precursor ion. Structures have been proposed for some dications and some quadruply charged ions. At pH 3 and 11, the mass spectra of NaCl clusters show the presence of mixed clusters of NaCl with HCl and NaOH, respectively. The effects of ionic radius on 20 distributions of cluster ions for 10 salts were investigated; however, the fine structure of these effects is not readily discerned.

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“…In this latter case, secondary ion molecular fragments (CsI) t I Ϫ were analyzed for 1 Յ t Յ 12. That the alkali halides, in general show power law spectra for 4 keV Ar ϩ and Xe ϩ primary ions was first shown by Barlak et al [34,35].…”

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confidence: 84%

Relationships between cluster secondary ion mass intensities generated by different cluster primary ions

Seah

Green

Gilmore

2010

J. Am. Soc. Mass Spectrom.

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Measurements are described to evaluate the constitution of secondary ion mass spectra for both monatomic and cluster primary ions. Previous work shows that spectra for different primary ions may be accurately described as the product of three material-dependent component spectra, two being raised to increasing powers as the cluster size increases. That work was for an organic material and, here, this is extended to (SiO 2 ) t OH Ϫ clusters from silicon oxide sputtered by 25 keV Bi n ϩ cluster primary ions for n ϭ 1, 3, and 5 and 1 Յ t Յ 15. These results are described to a standard deviation of 2.4% over 6 decades of intensity by the product of a constant with a spectrum, H SiOH ‫ء‬ , and a power law spectrum in t. This evaluation is extended, using published data for Si t ϩ sputtered from Si by 9 and 18 keV Au Ϫ and Au 3 Ϫ , with confirmation that the spectra are closely described by the product of a constant with a spectrum, H Si ‫ء‬ , and a simple spectrum that is an exponential dependence on t, both being raised to appropriate powers. This is confirmed with further published data for 6, 9, 12, and 18 keV Al Ϫ and Al 2 Ϫ primary cluster ions. In all cases, the major effect of intensity is then related to the deposited energy of the primary ion at the surface. The constitution of SIMS spectra, for monatomic and cluster primary ion sources, is shown, in all cases, to be consistent with the product of a constant with two component spectra raised to given powers. (J Am Soc Mass Spectrom 2010, 21, 370 -377) © 2010 American Society for Mass Spectrometry T he analysis of complex molecules in SIMS has been enhanced in recent years by the application of primary cluster ions of the type Au n Ϯ , Bi n ϩ , C 60 nϩ , etc. These provide significantly higher yields of the larger fragments that are important in the analysis of larger molecules. Over the years, there has not been a great focus on the relative intensities of the many secondary ions in the spectrum and their changes with the change in primary ion cluster size and energy. Analysts have usually focused on the enhancement of intensity of a particular characteristic ion obtained when using larger cluster primary ions. However, the fragment ions in the spectrum can be used to construct the structure of the molecules or the arrangement of atoms at a surface as well as provide important data as a function of depth in depth profiles [1][2][3][4][5][6][7][8]. Studies of the whole secondary ion spectrum and its evolution from one primary ion source to another are an important part of the infrastructure to the whole field of secondary ion mass spectrometry.Much historical data and data in spectral libraries [9 -11] are for inert gas primary ions. Over the years, the primary ion sources used have changed and changed again. Different spectrometer manufacturers fit different primary ion sources. It is important, therefore, if analysts are to make the best use of their instruments and of the published literature and data sources, that the relationships for the secondary ion ...

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Secondary ion mass spectrometry of metal halides. 3. Ionic radii effects in alkali halide clusters

Cited by 59 publications

References 3 publications

Studies in cluster ion formation. Part I. Fast atom bombardment mass spectrometry of tetraalkylammonium halides: Factors influencing cluster ion size and stability

Studies in cluster ion formation. Part I. Fast atom bombardment mass spectrometry of tetraalkylammonium halides: Factors influencing cluster ion size and stability

Electrospray ionization tandem mass spectrometric study of salt cluster ions. Part 1? Investigations of alkali metal chloride and sodium salt cluster ions

Relationships between cluster secondary ion mass intensities generated by different cluster primary ions

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