Reactions and thermochemistry of protonated methanol clusters produced by electron impact ionization

El‐Shall, M. Samy; Marks, C.; Sieck, L. Wayne; Meot‐Ner, Michael

doi:10.1021/j100184a007

Cited by 62 publications

(78 citation statements)

References 8 publications

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“…This kind of behavior has been observed earlier in electron impact ionization of methanol and methanol-water clusters by Garvey et al 15 and Elshall et al 29 The enhanced intensity of (CH 3 OH) 9 (H 2 O)H + was attributed to complete solvation of a core H 3 O + ion by nine methanol molecules surrounding it and leading to the maximum number of hydrogen bonds. 30 The authors also suggested that an efficient proton 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 transfer takes place from methanol to be incorporated into a fully solvated hydronium ion.…”

Section: Mass Spectrometry Of Mixed Methanol-water Clusterssupporting

confidence: 74%

Vacuum-Ultraviolet (VUV) Photoionization of Small Methanol and Methanol−Water Clusters

et al. 2008

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In this work we report on the vacuum-ultraviolet (VUV) photoionization of small methanol and methanol-water clusters. Clusters of methanol with water are generated via co-expansion of the gas phase constituents in a continuous supersonic jet expansion of methanol and water seeded in Ar. The resulting clusters are investigated by single photon ionization with tunable vacuumultraviolet synchrotron radiation and mass analyzed using reflectron mass spectrometry.

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Section: Mass Spectrometry Of Mixed Methanol-water Clusterssupporting

confidence: 74%

Vacuum-Ultraviolet (VUV) Photoionization of Small Methanol and Methanol−Water Clusters

et al. 2008

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“…3 is obtained with the TOFMS operated in the reflectron mode. This spectrum in- dicates the population distribution of cluster ions formed in the first field-free region within the time range of 1 -80 s. A strong intensity decrease for the parent cluster ion P 22 can be readily discerned. Note that P 21 is not significantly more intense than P 20 in Fig.…”

Section: Resultsmentioning

confidence: 67%

“…Many ionization techniques have also been employed to investigate methanol clusters ͑e.g., EI, 21,22 MPI, [23][24][25] and IR/vuv excitation 26 ͒. As found for water clusters, protonated methanol clusters dominate the mass spectra of ͑CH 3 OH͒ n : unprotonated ͑CH 3 OH͒ n + ͑n ഛ 7͒ are only observable in an Ar expansion.…”

Section: Introductionmentioning

confidence: 70%

“…21 The possible relationship between methanol cluster ion distributions and methanol cluster distributions has been addressed by Shi et al 27 and Fu et al 26 based on single photon vuv ͑118 nm͒ laser ionization. Formation of H + ͑H 2 O͒͑CH 3 OH͒ n and ͑CH 3 OH͒ n ͓͑CH 3 ͒ 2 O͔H + clusters via two kinds of intramolecular ion-molecule reactions are observed for EI ionization, 21,22 but not for single photon ͑118 nm͒ ionization. 26,27 Ammonia is another important solvent species: it is characterized by van der Waals, but not hydrogen bonding, interactions, as it is a very poor proton donor, albeit a very good proton acceptor ͓ammonia proton affinity PA͑NH 3 ͒ ϳ 204 kcal/ mol ͑Ref.…”

Section: Introductionmentioning

confidence: 97%

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Dynamics and fragmentation of van der Waals clusters: (H2O)n, (CH3OH)n, and (NH3)n upon ionization by a 26.5eV soft x-ray laser

Dong

Heinbuch

Rocca

et al. 2006

The Journal of Chemical Physics

102

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A tabletop soft x-ray laser is applied for the first time as a high energy photon source for chemical dynamics experiments in the study of water, methanol, and ammonia clusters through time of flight mass spectroscopy. The 26.5 eV/photon laser ͑pulse time duration of ϳ1 ns͒ is employed as a single photon ionization source for the detection of these clusters. Only a small fraction of the photon energy is deposited in the cluster for metastable dissociation of cluster ions, and most of it is removed by the ejected electron. Protonated water, methanol, and ammonia clusters dominate the cluster mass spectra. Unprotonated ammonia clusters are observed in the protonated cluster ion size range 2 ഛ n ഛ 22. The unimolecular dissociation rate constants for reactions involving loss of one neutral molecule are calculated to be ͑0.6-2.7͒ ϫ 10 4 , ͑3.6-6.0͒ ϫ 10 3 , and ͑0.8-2.0͒ ϫ 10 4 s −1 for the protonated water ͑9 ഛ n ഛ 24͒, methanol ͑5 ഛ n ഛ 10͒, and ammonia ͑5 ഛ n ഛ 18͒ clusters, respectively. The temperatures of the neutral clusters are estimated to be between 40 and 200 K for water clusters ͑10ഛ n ഛ 21͒, and 50-100 K for methanol clusters ͑6 ഛ n ഛ 10͒. Products with losses of up to five H atoms are observed in the mass spectrum of the neutral ammonia dimer. Large ammonia clusters ͑NH 3 ͒ n ͑n Ͼ 3͒ do not lose more than three H atoms in the photoionization/ photodissociation process. For all three cluster systems studied, single photon ionization with a 26.5 eV photon yields near threshold ionization. The temperature of these three cluster systems increases with increasing cluster size over the above-indicated ranges.

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“…[15][16][17] This similarity suggests that it is the stability of the products, rather than the specifics of the reaction dynamics, that determines the chemical outcome. A detailed review and discussion of previous findings for both methanol and other alcohol clusters has been provided by Garvey et al…”

Section: Introductionmentioning

confidence: 99%

Electron-driven ionization of large methanol clusters in helium nanodroplets

Goulart

Bartl

Mauracher

et al. 2013

Phys. Chem. Chem. Phys.

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The electron-driven ionization of helium droplets doped with pure methanol and ethanol clusters has been investigated for the first time using high resolution mass spectrometry. Large clusters are readily accessible by this route, with up to 100 alcohol molecules seen in the present study. The mass spectra for the doped helium droplets show many similarities with previous gas phase mass spectrometric studies of methanol and ethanol clusters. Thus the dominant ion products, at least for small clusters, are

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Reactions and thermochemistry of protonated methanol clusters produced by electron impact ionization

Cited by 62 publications

References 8 publications

Vacuum-Ultraviolet (VUV) Photoionization of Small Methanol and Methanol−Water Clusters

Vacuum-Ultraviolet (VUV) Photoionization of Small Methanol and Methanol−Water Clusters

Dynamics and fragmentation of van der Waals clusters: (H2O)n, (CH3OH)n, and (NH3)n upon ionization by a 26.5eV soft x-ray laser

Electron-driven ionization of large methanol clusters in helium nanodroplets

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