Vibrational spectroscopy of the hydrated hydronium cluster ions H3O+⋅(H2O)<i>n</i> (<i>n</i>=1, 2, 3)

Yeh, L. I.; Okumura, Mitchio; Myers, James D.; Price, Joseph A.; Lee, Yuan T.

doi:10.1063/1.457305

Cited by 471 publications

(368 citation statements)

References 51 publications

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“…The parent ions are then guided into a 22-pole ion trap, where they are cooled in collisions with cold He and interrogated by UV photofragment spectroscopy. To enhance the dissociation yield after UV excitation, the ions are further irradiated with a pulse from a CO 2 laser [30,31]. In the case of bradykinin, the only laser-induced dissociation channel observed is the loss of the neutral phenylalanine side chain.…”

Section: Methodsmentioning

confidence: 99%

Conformational Distribution of Bradykinin [bk + 2 H]²⁺ Revealed by Cold Ion Spectroscopy Coupled with FAIMS

Παπαδόπουλος

Svendsen

Boyarkin

et al. 2012

J. Am. Soc. Mass Spectrom.

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We employ cold ion spectroscopy (CIS) in conjunction with high-field asymmetric waveform ion mobility spectrometry (FAIMS) to study the peptide bradykinin in its doubly protonated charge state ([bk+2 H] 2+ ). Using FAIMS, we partially separate the electrosprayed [bk+2 H] 2+ ions into two conformational families and selectively introduce one of them at a time into a cold ion trap mass spectrometer, where we probe them by UV photofragment spectroscopy. Although the two conformational families have distinct electronic spectra, some cross-conformer contamination can be observed under certain conditions. We demonstrate that this contamination comes from isomerization of ions energized during and/or after their separation and not from incomplete separation of the initially electrosprayed conformations in the FAIMS stage. By varying the injection voltage of the ions into our mass spectrometer, we can intentionally induce isomerization to produce what seems to be a gas phase equilibrium distribution of conformers. This distribution is different from the one produced initially by electrospray, indicating that some of the conformers are kinetically trapped and may be related to conformers that are more favored in solution.

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Section: Methodsmentioning

confidence: 99%

Conformational Distribution of Bradykinin [bk + 2 H]²⁺ Revealed by Cold Ion Spectroscopy Coupled with FAIMS

Παπαδόπουλος

Svendsen

Boyarkin

et al. 2012

J. Am. Soc. Mass Spectrom.

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“…[34]. It should be noted that combination of tunable IR laser with line tunable CO 2 laser has been used previously [35,36]. Finally an auxiliary CO 2 laser can also be useful for enhancing the spectroscopic sensitivity using the IR FEL at long wavelength, for probing metal-ligand modes for example [37].…”

Section: Mass Spectrometry and Irmpd Spectroscopymentioning

confidence: 99%

Diagnosing the Protonation Site of b₂ Peptide Fragment Ions using IRMPD in the X–H (X = O, N, and C) Stretching Region

Sinha

Erlekam

Bythell

et al. 2011

J. Am. Soc. Mass Spectrom.

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Charge-directed fragmentation has been shown to be the prevalent dissociation step for protonated peptides under the low-energy activation (eV) regime. Thus, the determination of the ion structure and, in particular, the characterization of the protonation site(s) of peptides and their fragments is a key approach to substantiate and refine peptide fragmentation mechanisms. Here we report on the characterization of the protonation site of oxazolone b 2 ions formed in collision-induced dissociation (CID) of the doubly protonated tryptic model-peptide YIGSR. In support of earlier work, here we provide complementary IR spectra in the 2800-3800 cm -1 range acquired on a table-top laser system. Combining this tunable laser with a high power CO 2 laser to improve spectroscopic sensitivity, well resolved bands are observed, with an excellent correspondence to the IR absorption bands of the ring-protonated oxazolone isomer as predicted by quantum chemical calculations. In particular, it is shown that a band at 3445 cm -1 , corresponding to the asymmetric N-H stretch of the (nonprotonated) N-terminal NH 2 group, is a distinct vibrational signature of the ring-protonated oxazolone structure.

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“…Lee and coworkers (14) used vibrational spectroscopy to obtain clear evidence of the rearrangement of the NO + (H 2 O) n cluster by observing the appearance of new hydrogen (H)-bonded OH stretching lines. Using quantum molecular dynamics, Ye and Cheng (15) suggested possible structures and corresponding IR spectra for NO + (H 2 O) n (n = 1-3) clusters.…”

mentioning

confidence: 99%

Resolving the HONO formation mechanism in the ionosphere via ab initio molecular dynamic simulations

Zhong

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Solar emission produces copious nitrosonium ions (NO + ) in the D layer of the ionosphere, 60 to 90 km above the Earth's surface. NO + is believed to transfer its charge to water clusters in that region, leading to the formation of gaseous nitrous acid (HONO) and protonated water cluster. The dynamics of this reaction at the ionospheric temperature (200-220 K) and the associated mechanistic details are largely unknown. Using ab initio molecular dynamics (AIMD) simulations and transition-state search, key structures of the water hydrates-tetrahydrate NO + (H 2 O) 4 and pentahydrate NO + (H 2 O) 5 -are identified and shown to be responsible for HONO formation in the ionosphere. The critical tetrahydrate NO + (H 2 O) 4 exhibits a chainlike structure through which all of the lowest-energy isomers must go. However, most lowest-energy isomers of pentahydrate NO + (H 2 O) 5 can be converted to the HONO-containing product, encountering very low barriers, via a chain-like or a three-armed, star-like structure. Although these structures are not the global minima, at 220 K, most lowest-energy NO + (H 2 O) 4 and NO + (H 2 O) 5 isomers tend to channel through these highly populated isomers toward HONO formation.ionosphere | HONO | mechanism | water | clusters T he ionosphere is the largest layer in the Earth's atmosphere, ranging in altitude from ∼60 to 1,000 km and includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere contains a high concentration of electrons and ions because of the ionization of gases in that region by short wavelength radiation from the Sun. Therefore, these species play an important role in atmospheric electricity, influencing radio propagation to different regions on the Earth's surface and space-based navigational systems (1). The D layer is the innermost layer of the ionosphere, ranging from 60 to 90 km in altitude, where Lyman series-α hydrogen radiation from the Sun gives rise to abundant nitrosonium ions (NO + ). In addition to the ionospheric reaction between NO + and water, explorations of the chemical reactivity of NO + and water clusters (2-4) have implications for understanding the mechanisms of atmospherically relevant reactions in water clusters (5-9).Over the past two decades, several experimental and theoretical studies (10-13) have focused on understanding the chemical and physical properties of the small-sized hydrated nitrosonium ion NO + (H 2 O) n , where n = 1-5. Two key processes have been proposed for HONO formation: NO + ðH 2 OÞ n + H 2 O → fðHONOÞH + ðH 2 OÞ n É → H + ðH 2 OÞ n + HONO .[1]Lee and coworkers (14) used vibrational spectroscopy to obtain clear evidence of the rearrangement of the NO + (H 2 O) n cluster by observing the appearance of new hydrogen (H)-bonded OH stretching lines. Using quantum molecular dynamics, Ye and Cheng (15) suggested possible structures and corresponding IR spectra for NO + (H 2 O) n (n = 1-3) clusters. In a major experimental breakthrough, Relph et al. (16) showed that the extent to which reaction 1 produces HONO ...

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Vibrational spectroscopy of the hydrated hydronium cluster ions H3O+⋅(H2O)n (n=1, 2, 3)

Cited by 471 publications

References 51 publications

Conformational Distribution of Bradykinin [bk + 2 H]²⁺ Revealed by Cold Ion Spectroscopy Coupled with FAIMS

Conformational Distribution of Bradykinin [bk + 2 H]²⁺ Revealed by Cold Ion Spectroscopy Coupled with FAIMS

Diagnosing the Protonation Site of b₂ Peptide Fragment Ions using IRMPD in the X–H (X = O, N, and C) Stretching Region

Resolving the HONO formation mechanism in the ionosphere via ab initio molecular dynamic simulations

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Vibrational spectroscopy of the hydrated hydronium cluster ions H3O+⋅(H2O)n (n=1, 2, 3)

Cited by 471 publications

References 51 publications

Conformational Distribution of Bradykinin [bk + 2 H]2+ Revealed by Cold Ion Spectroscopy Coupled with FAIMS

Conformational Distribution of Bradykinin [bk + 2 H]2+ Revealed by Cold Ion Spectroscopy Coupled with FAIMS

Diagnosing the Protonation Site of b2 Peptide Fragment Ions using IRMPD in the X–H (X = O, N, and C) Stretching Region

Resolving the HONO formation mechanism in the ionosphere via ab initio molecular dynamic simulations

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Conformational Distribution of Bradykinin [bk + 2 H]²⁺ Revealed by Cold Ion Spectroscopy Coupled with FAIMS

Conformational Distribution of Bradykinin [bk + 2 H]²⁺ Revealed by Cold Ion Spectroscopy Coupled with FAIMS

Diagnosing the Protonation Site of b₂ Peptide Fragment Ions using IRMPD in the X–H (X = O, N, and C) Stretching Region