Negative ion–molecule reactions of ozone and their implications on the thermochemistry of O3−

Lifshitz, Chava; Wu, Richard L. C.; Tiernan, T. O.; Terwilliger, D. T.

doi:10.1063/1.435489

Cited by 165 publications

(86 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…(15) is evaluated numerically. A similar convolution with the kinetic energy distribution P(E cm ion , E cm ) of the educt ions would be desirable, such as the one applied in GIB by Lifshitz et al 29 In (8)). In the convolution, E cm in Eqn (15) …”

Section: Data Evaluationmentioning

confidence: 98%

Energy resolved measurement of endothermic reaction and dissociation thresholds: Fourier transform ion cyclotron resonance mass spectrometry meets guided ion beam

Beyer

Bondybey

1997

Rapid Commun. Mass Spectrom.

View full text Add to dashboard Cite

Performance of energy resolved measurements of endothermic reaction and of collision-induced dissociation thresholds can be improved if relative or absolute cross sections are evaluated, rather than product intensities. The calculation of cross sections from measured ion intensities is shown for Fourier transform ion cyclotron resonance mass spectrometry, which provides the link to corresponding experiments with other techniques such as guided ion beam. The peculiarities of the Fourier transform experiment are discussed, and a convolution with the ion kinetic energy distribution is presented for highly accurate threshold fits. © 1997 by John Wiley & Sons, Ltd. Received 9 June 1997; Accepted 30 June 1997 Rapid. Commun. Mass Spectrom. 11, 1588-1591(1997 Numerous energy dependent studies of both endothermic reactions 1-5 and collision-induced dissociation (CID) [6][7][8][9][10][11][12][13][14] have shown that Fourier transform ion cyclotron resonance (FTICR) mass spectrometry is a valuable tool for determining threshold energies. And indeed, the ease of ion selection and control of excitation energy and the high mass accuracy and mass range are ideal prerequisites for energy-resolved measurements. In spite of these apparent advantages of FTICR, the published data can rarely compete in accuracy with those from guided ion beam 15 (GIB) measurements, such as those routinely performed in the group of Armentrout. [16][17][18][19] In the present publication, the idea is put forward that this may partly be due to the different data evaluation procedures applied. GIB data are generally converted to cross sections, while it is relative or absolute intensities that have been evaluated in FTICR. The cross section, however, is the physical quantity that carries the information about the collision. The calculation of an absolute or relative cross section could thus provide the link between FTICR and GIB. This is shown, together with the data evaluation procedure following the standard GIB approach. Data are presented to illustrate the qualitative threshold behaviour, and some aspects concerning the accuracy of energy resolved FTICR threshold experiments are discussed. Finally, a convolution with the ion kinetic energy distribution is presented that is thought to yield very high accuracy for thermalized ions. EXPERIMENTAL PROCEDUREThe experimental procedure has been described previously;1-14 therefore a brief summary is sufficient for the purpose of the present work. Typically, the ions are stored in the ICR cell and mass selected by radio frequency (RF) excitation of unwanted ions. The selected educt ion of mass m ed is then accelerated to the desired energy E lab by an RF pulse of known amplitude E 1 and duration t exc . The educt ion is allowed to collide for some time t coll with the reactant or collision gas molecules of mass m coll present in the cell region at a constant pressure p, followed by recording of the mass spectrum. This is done several times for signal averaging, and the whole experiment is repeated at differe...

show abstract

Section: Data Evaluationmentioning

confidence: 98%

Energy resolved measurement of endothermic reaction and dissociation thresholds: Fourier transform ion cyclotron resonance mass spectrometry meets guided ion beam

Beyer

Bondybey

1997

Rapid Commun. Mass Spectrom.

View full text Add to dashboard Cite

show abstract

“…This was first recognized by Chantry [35], who outlined the mathematical treatment required for the kinetic energy distribution of the neutral species. Lifshitz et al later extended this to include the kinetic energy distribution of the ionic reactant [36]. The importance of this effect can be seen by examining Figure 5, which shows cross sections for reaction 3 [20].…”

Section: Translational Motion Of the Reactants: Doppler Broadeningmentioning

confidence: 99%

Mass spectrometry—Not just a structural tool: The use of guided ion beam tandem mass spectrometry to determine thermochemistry

Armentrout

2002

J. Am. Soc. Mass Spectrom.

175

180

View full text Add to dashboard Cite

Guided ion beam tandem mass spectrometry has proved to be a robust tool for the measurement of thermodynamic information. Over the past twenty years, we have elucidated a number of factors necessary to make such thermochemistry accurate. Careful attention must be paid to the reduction of the raw data, ion intensities versus laboratory ion energies, to a more useful form, reaction cross sections versus relative kinetic energy. Analysis of the kinetic energy dependence of cross sections for endothermic reactions can then reveal thermodynamic data for both bimolecular and collision-induced dissociation (CID) processes. Such analyses need to include consideration of the explicit kinetic and internal energy distributions of the reactants, the effects of multiple collisions, the identity of the collision partner in CID processes, the kinetics of the reaction being studied, and competition between parallel reactions. This work provides examples illustrating the need to consider this multitude of effects along with details of the procedures developed in our group for handling each of them. ( W hen does a mass spectrometer become an ion beam instrument? Is this defined by the instrument, by whether the operator is an analytical or physical chemist, or by the experiments done? All mass spectrometers utilize ion beams, but the unspoken definition of an ion beam instrument is an apparatus that can be used to make quantitative physical measurements. In this regard, the capabilities of the instrumentation and the intent and training of the operator are all important factors. Whereas a mass spectrometer is often used as an identification tool through the use of mass spectral patterns, by taking advantage of the ability to easily change the kinetic energy of ions, it can also be a powerful instrument for the determination of thermodynamic data.In this article, I lay down some of the founding principles behind our use of tandem mass spectrometry, and in particular, so-called guided ion beam mass spectrometry to elucidate thermochemical information. This is achieved primarily by examining the kinetic energy dependence of endothermic ion-molecule reactions and determining their energy thresholds.Although many types of instruments have been used to perform such measurements, the link between such studies and guided ion beam techniques is a strong one. Indeed, the NIST Webbook [1] states in its section on Determinations of Reaction Endothermicity that "more commonly a so-called guided-beam apparatus is utilized for such determinations." Considering that there are only about a dozen such laboratories worldwide, this is a testament to the ability of this particular kind of apparatus to provide a plethora of high quality information. However, such information requires attention to myriad details, which are outlined in this article.Two fundamental types of reactions can be used to acquire thermodynamic information: Bimolecular exchange reactions, process 1, and collision-induced dissociation (CID), process 2.Reactions 1 can be either ex...

show abstract

“…The summation is over the rovibrational states of the reactant ions i, where E i is the excitation energy of each state and g i is the fractional population of those states (Α g i ϭ 1). Before comparison with experimental data, eq 1 is convoluted to account for the kinetic energy of the reactant ion and thermal broadening of the neutral gas [29,30].…”

Section: Thermochemical Analysismentioning

confidence: 99%

An electrospray ionization source for thermochemical investigation with the guided ion beam mass spectrometer

Moision

Armentrout

2007

J. Am. Soc. Mass Spectrom.

100

157

View full text Add to dashboard Cite

An electrospray ionization (ESI) source developed for use with the guided ion beam tandem mass spectrometer (GIBMS) is described. For accurate determination of thermochemistry using threshold collision-induced dissociation (TCID), it is essential that any source produces ions with four exacting characteristics: (1) high intensity, (2) stable signal, and well-defined energies both (3) kinetic, and (4) internal. To accomplish these objectives, the ions generated by the electrospray are collected using a radio frequency electrodynamic ion funnel and are then transferred into a hexapole ion guide where they are thermalized and subsequently passed into higher-vacuum regions for analysis. The resulting ion intensities using this source can exceed 10 6 ions/s. Stable beams (Ͻ10% variation in signal) can be generated over multiple hours. The kinetic energy distribution of ions emerging from this source has been shown to be well described by a Gaussian distribution with a full width half maximum (FWHM) of about 0.1-0.2 eV in the laboratory frame of reference. Finally, TCID results for ions generated with this source show excellent agreement with previously reported threshold values for ions generated using a variety of sources and experimental methodologies. This confirms that internal energies of the ions are well described by a Maxwell-Boltzmann distribution at room temperature. ( , electrospray ionization (ESI) has become a widely used source for mass spectrometry. The popularity of the ESI can be credited to a number of factors. In addition to its ability to gently transfer large biological molecules into the gas phase in multiple charge states, ESI sources benefit from being simple in design and robust in use. However, despite its widespread acceptance, the ESI source has been used in only a limited number of experiments for quantitative determination of thermochemical information [2][3][4][5][6]. This is unfortunate, given the ability of the ESI to easily produce a large number of interesting gas-phase biological ions [7][8][9], charged transition metals [10 -12], and alkali metal/ligand complexes [12][13][14]. The scarcity of thermochemical data originating from the ESI most likely lies in the difficulty of producing an ion beam that is suitable for rigorous thermochemical analysis. These prior ESI studies [2][3][4][5][6], where simpler ESI sources have been used to generate ions, have not thoroughly demonstrated whether such conditions (outlined below) have been reached.Threshold collision-induced dissociation (TCID) experiments represent a well-established means of obtaining accurate thermochemical data for a diverse range of gas-phase ions [15][16][17][18][19][20]. Essentially, TCID consists of systematically varying the kinetic energy of a mass selected ion beam and then colliding the ions with a stationary non-reactive gas such as xenon. With increasing collision energy, the parent ion begins to fragment into products that are then collected as a function of the collision energy. The resulting data may be mod...

show abstract

Negative ion–molecule reactions of ozone and their implications on the thermochemistry of O3−

Cited by 165 publications

References 47 publications

Energy resolved measurement of endothermic reaction and dissociation thresholds: Fourier transform ion cyclotron resonance mass spectrometry meets guided ion beam

Energy resolved measurement of endothermic reaction and dissociation thresholds: Fourier transform ion cyclotron resonance mass spectrometry meets guided ion beam

Mass spectrometry—Not just a structural tool: The use of guided ion beam tandem mass spectrometry to determine thermochemistry

An electrospray ionization source for thermochemical investigation with the guided ion beam mass spectrometer

Contact Info

Product

Resources

About