Spectroscopy of Li+·Rg and Li+–Rg transport coefficients (Rg = He–Rn)

Lozeille, Jérôme; Winata, Ervina; Soldán, Pavel; Lee, Edmond P. F.; Viehland, Larry A.; Wright, Timothy G.

doi:10.1039/b111675d

Cited by 49 publications

(48 citation statements)

References 38 publications

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“…Based on previous results [1][2][3][4][5][6][7][8][9][10][11][12][13][14] and assuming that the present interaction potentials are accurate, we expect that the ion mobilities reported here are accurate to within about 0.2%. This is true both for the mobilities at fixed T 0 as a function of E / n 0 and for the zero-field mobilities as a function of T 0 .…”

Section: Discussionsupporting

confidence: 69%

“…To date, we have studied 3 He + and 4 He + , 1 Cl − , 2 the alkali metal cations, [3][4][5][6] O − , 7 I − , 8 S − , 9 Hg + and Cd + , 10 O + , 11 F − , 12 Br − , 13 and Tl + . 14 Values calculated from our interaction potentials are in good to excellent agreement with experimental data where they exist, and in each case our potential was found either to be in agreement with the best potential available elsewhere or to be actually the best potential available.…”

Section: Introductionmentioning

confidence: 99%

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Interaction potentials and transport properties of coinage metal cations in rare gases

Yousef

Shrestha

Viehland

et al. 2007

The Journal of Chemical Physics

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103

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High-level ab initio calculations are performed on the coinage metal cations ͑Cu + , Ag + , and Au + ͒ interacting with each of the rare gases ͓Rg ͑Rg=He to Rn͔͒. The RCCSD͑T͒ procedure is employed, with basis sets being of approximately quintuple-quality, but with the heavier species using relativistic effective core potentials. The interaction potentials are compared to experimental and theoretical data where they exist. In addition, transport coefficients for the mobility and diffusion of the cations in the rare gases are calculated. The latter have involved a rewriting of some of the programs used, and the required modifications are discussed. The mobility results indicate that, rather than being a rare occurrence, mobility minima may be common phenomena. Finally, a new estimate is put forward for the validity of zero-field mobilities in ion mobility spectrometry.

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Section: Discussionsupporting

confidence: 69%

Section: Introductionmentioning

confidence: 99%

Interaction potentials and transport properties of coinage metal cations in rare gases

Yousef

Shrestha

Viehland

et al. 2007

The Journal of Chemical Physics

Self Cite

103

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“…[8][9][10][11] These are all closed-shell systems that serve as prototypes of cation/rare-gas interactions, as discussed in detail by Bellert and Breckenridge. 12 Very recently, we also tackled the more demanding open-shell system of O − with the three lightest rare gases, where it was shown 13 that it was important to employ potentials which took account of the spin-orbit interaction; this arises owing to the production of 2 ⌸ and 2 ⌺ + states upon interaction of the O − with the rare gas, and the interaction between the two ⍀ =1/2 states thereafter.…”

Section: Introductionmentioning

confidence: 99%

Interaction potentials and spectroscopy of Hg+∙Rg and Cd+∙Rg and transport coefficients for Hg+ and Cd+ in Rg (RgHeRn)

Qing

Viehland

Lee

et al. 2006

The Journal of Chemical Physics

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High-level ab initio calculations have been performed on the Hg + · Rg and Cd + · Rg species, where Rgv Heu Rn. Potential-energy curves have been calculated over a wide range of internuclear separation, sampling the repulsive, equilibrium, and long-range regions. From these curves, rovibrational and spectroscopic constants were derived and compared to those available from previous studies. In addition, transport coefficients were calculated and compared to the available experimental data for the cases of Hg + in He, Ne, and Ar. There are two interesting features relating to the mobility results. One is the development of a "mobility minimum" for Hg + in the heavier rare gases-with weaker minima being found for Cd + ; a "rule of thumb" is presented for determining when mobility minima might appear. The second is that excellent agreement is found for the direct calculation of mobilities for Hg + in 22 Ne, and those obtained by scaling the 20 Ne mobilities. The latter result allows us to conclude that the mobilities of the various combinations of isotopes can be calculated from the results herein via a mass scaling.

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“…The key to rational design of FAIMS separations is a priori calculation of K(E) for any ion/buffer gas pair. So far, this has been possible only when both the ion and buffer gases are monatomic, which creates an isotropic interaction potential that permits accurate scattering calculations [31,32]. For polyatomic ions, experiments have revealed that, in general, small ions including all monatomic species and nearly all small organic ions (including amino acids) belong to Type A, large and macromolecular ions such as proteins and polypeptides belong to Type C, and Type B is represented by relatively few intermediate-size species.…”

mentioning

confidence: 99%

FAIMS operation for realistic gas flow profile and asymmetric waveforms including electronic noise and ripple

Shvartsburg

Tang

Smith

2005

J. Am. Soc. Mass Spectrom.

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The use of field asymmetric waveform ion mobility spectrometry (FAIMS) has rapidly grown with the advent of commercial FAIMS systems coupled to mass spectrometry. However, many fundamental aspects of FAIMS remain obscure, hindering its technological improvement and expansion of analytical utility. Recently, we developed a comprehensive numerical simulation approach to FAIMS that can handle any device geometry and operating conditions. The formalism was originally set up in one dimension for a uniform gas flow and limited to ideal asymmetric voltage waveforms. Here we extend the model to account for a realistic gas flow velocity distribution in the analytical gap, axial ion diffusion, and waveform imperfections (e.g., noise and ripple). The nonuniformity of the gas flow velocity profile has only a minor effect, slightly improving resolution. Waveform perturbations are significant even at very low levels, in some cases ϳ0.01% of the nominal voltage. These perturbations always improve resolution and decrease sensitivity, a trade-off controllable by variation of noise or ripple amplitude. This trade-off is physically inferior to that obtained by adjusting the gap width and/or asymmetric waveform frequency. However, the disadvantage is negligible when the perturbation period is much shorter than the residence time in FAIMS, and ripple adjustment appears to offer a practical method for modifying FAIMS resolution. S eparation of ions in the gas-phase using field asymmetric waveform ion mobility spectrometry (FAIMS) extends back two decades [1][2][3][4][5][6][7]. However, FAIMS was not widely used until its coupling to electrospray ionization mass spectrometry [8,9], which has expanded its utility to environmental [10 -13] and biological [14 -18] applications, in addition to traditional detection of airborne volatiles [19 -23]. The recent advent of commercial FAIMS systems (Ionalytics Selectra [17,24] and Sionex DMS [23,25]) is increasing the acceptance of FAIMS and diversifying its applications.While FAIMS analyses have become increasingly common, the fundamentals remain relatively poorly understood [18]. Phenomenologically, ions are separated by the difference between mobilities at high and low electric fields (E) (respectively K H and K L ) that in general differ as ion mobilities in gases depend on the field. Thus, FAIMS measures the mean derivative of mobility with respect to field ͗ѨK⁄ѨE͘ (over a certain range of E), in contrast to the conventional ion mobility spectrometry [26,27] that determines absolute mobilities (K). The K(E) function can be expressed as a polynomial over even powers of E/N, where N is the buffer gas number density [28,29]:Mobilities tend to significantly deviate from zero-field values K(0) at E/N Ն ϳ30 to 40 Td, which defines the lower limit for electric fields useful in FAIMS operation. The upper limit is given by the onset of electrical breakdown in gas, which depends on the gas identity and number density, and (to a lesser extent) the width and geometry of the gap between electrodes (the...

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Spectroscopy of Li+·Rg and Li+–Rg transport coefficients (Rg = He–Rn)

Cited by 49 publications

References 38 publications

Interaction potentials and transport properties of coinage metal cations in rare gases

Interaction potentials and transport properties of coinage metal cations in rare gases

Interaction potentials and spectroscopy of Hg+∙Rg and Cd+∙Rg and transport coefficients for Hg+ and Cd+ in Rg (RgHeRn)

FAIMS operation for realistic gas flow profile and asymmetric waveforms including electronic noise and ripple

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