Reaction dynamics of temperature-variable anion water clusters studied with crossed beams and by direct dynamics

Otto, R.; Xie, Jing; Brox, J.; Trippel, Sebastian; Stei, Martin; Best, Thorsten; Siebert, Matthew R.; Hase, William L.; Wester, Roland

doi:10.1039/c2fd20013a

Cited by 58 publications

(89 citation statements)

References 33 publications

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“…This will allow further investigations of the efficiency of thermalisation of the rotational and vibrational degrees of freedom by buffer gas cooling under different trapping conditions. The information is also useful for internal state-dependent collision and reaction studies, and has recently already been employed in reactions of H 3 O − 2 with CH 3 I 25,26 . Furthermore, photodetachment spectroscopy is an important prerequisite for high resolution terahertz spectroscopy of low-lying rotational and vibrational states in such systems, because it allows for action spectroscopic detection of inernal excitations on the fewmolecule level.…”

Section: Resultsmentioning

confidence: 99%

Internal state thermometry of cold trapped molecular anions

Otto

Zastrow

Best

et al. 2013

Phys. Chem. Chem. Phys.

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− 2 anions has been performed in a cryogenic 22-pole radiofrequency multipole trap. Measurements of the detachment cross section as a function of laser frequency near threshold have been analysed. Using this bound-free spectroscopy approach we could demonstrate rotational and vibrational cooling of the trapped anions by the buffer gas in the multipole trap. Below 50 K the OH − rotational temperature shows deviations from the buffer gas temperature, and possible causes for this are discussed. For H 3 O − 2 vibrational cooling of the lowest vibrational quantum states into the vibrational ground state is observed. Its photodetachment cross section near threshold is modelled with a Franck-Condon model, with a detachment threshold that is lower, but still in agreement with the expected threshold for this system.

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Section: Resultsmentioning

confidence: 99%

Internal state thermometry of cold trapped molecular anions

Otto

Zastrow

Best

et al. 2013

Phys. Chem. Chem. Phys.

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“…The addition of a small number of solvent molecules to gas-phase ions provides insight into this transition. Recent investigations of microsolvated ions have addressed the impact of solvation on mechanisms [2], reactivity [3], reaction dynamics [4][5][6][7][8], vibrational energy transfer [9,10], and delocalization of charge [11].…”

Section: Introductionmentioning

confidence: 99%

Effect of higher order solvation and temperature on SN2 and E2 reactivity

Eyet

Melko

Ard

et al. 2015

International Journal of Mass Spectrometry

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“…[1][2][3][4][5][6][7][8][9][10] The traditional potential energy surface (PES) for this reaction has an ion-dipole X À ---CH 3 Y pre-reaction complex, a [X--CH 3 --Y] À central barrier, and an ion-dipole XCH 3 ---Y À post-reaction complex, all of C 3v symmetry. the OH À + CH 3 F S N 2 reaction with a CH 3 OH---F À post-reaction complex in which F À is hydrogenbonded to the -OH moiety, 11 and the F À + CH 3 I reaction with a hydrogen-bonded F À ---HCH 2 I pre-reaction complex. the OH À + CH 3 F S N 2 reaction with a CH 3 OH---F À post-reaction complex in which F À is hydrogenbonded to the -OH moiety, 11 and the F À + CH 3 I reaction with a hydrogen-bonded F À ---HCH 2 I pre-reaction complex.…”

Section: Introductionmentioning

confidence: 99%

Comparison of direct dynamics simulations with different electronic structure methods. F⁻ + CH₃I with MP2 and DFT/B97-1

Sun

Davda

Zhang

et al. 2015

Phys. Chem. Chem. Phys.

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In previous work, ion imaging experiments and direct chemical dynamics simulations with DFT/B97-1 were performed to study the atomic-level dynamics of the F(-) + CH3I → FCH3 + I(-) SN2 nucleophilic substitution reaction at different collision energies. Overall, the simulations are in quite good agreement with experiment at the low collision energy of 0.32 eV, however there are differences between experiment and simulation at the high collision energy of 1.53 eV. A recent CCSD(T) study of the potential energy surface for the F(-) + CH3I → FCH3 + I(-) SN2 reaction shows that it has both a traditional C3v and a hydrogen-bond entrance channel. They are represented by MP2 but not by B97-1, which has only the latter channel. On the other hand, B97-1 gives a reaction exothermicity in excellent agreement with experiment, while MP2 is in error by 24.3 kJ mol(-1). In the work presented here, direct dynamics simulations using MP2/aug-cc-pvdz/ECP/d were performed for the F(-) + CH3I → FCH3 + I(-) reaction at a 1.53 eV collision energy. The same direct rebound and stripping and indirect atomistic reaction mechanisms are found in the B97-1 and MP2 simulations. Both the B97-1 and MP2 simulations agree with the experimental fraction of the available product energy partitioned to CH3F internal energy, i.e. fint = 0.59 ± 0.08. However, the MP2 fint distribution is broader and in better agreement with experiment than B97-1. The two simulations methods give the same product energy partitioning for the stripping mechanism, but different partitionings for the rebound and indirect mechanisms. Compared to experiment, the principal difference between the B97-1 and MP2 results is the differential cross section which is nearly isotropic for B97-1. For MP2 backward scattering is more important than forward, as found in the experiments. Though there is no overall barrier for the reaction, B97-1 gives a reaction cross section appreciably larger than that for MP2, i.e. 8.6 ± 2.2 Å(2)versus 1.8 ± 0.3 Å(2). For B97-1 59% of the reaction consists of indirect mechanisms, while for MP2 the indirect mechanisms only comprise 11% of the reaction. The experimental differential cross section is more consistent with the atomistic mechanisms for MP2 than for B97-1.

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Reaction dynamics of temperature-variable anion water clusters studied with crossed beams and by direct dynamics

Cited by 58 publications

References 33 publications

Internal state thermometry of cold trapped molecular anions

Internal state thermometry of cold trapped molecular anions

Effect of higher order solvation and temperature on SN2 and E2 reactivity

Comparison of direct dynamics simulations with different electronic structure methods. F⁻ + CH₃I with MP2 and DFT/B97-1

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Reaction dynamics of temperature-variable anion water clusters studied with crossed beams and by direct dynamics

Cited by 58 publications

References 33 publications

Internal state thermometry of cold trapped molecular anions

Internal state thermometry of cold trapped molecular anions

Effect of higher order solvation and temperature on SN2 and E2 reactivity

Comparison of direct dynamics simulations with different electronic structure methods. F− + CH3I with MP2 and DFT/B97-1

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Comparison of direct dynamics simulations with different electronic structure methods. F⁻ + CH₃I with MP2 and DFT/B97-1