Stimulated emission pumping studies of energy transfer in highly vibrationally excited molecules

Yang, Xiujuan; Price, Joseph A.; Mack, J. A.; Morgan, C. G.; Rogaski, C. A.; McGuire, David; Kim, E. H.; Wodtke, Alec M.

doi:10.1021/j100118a005

Cited by 62 publications

(50 citation statements)

References 9 publications

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“…Various optical preparation schemes such as visible, 1 infrared, 2,3 or Raman pumping 4,5 are often used to meet this goal. However, many of these experiments are made difficult by the inability to transfer large populations to a desirable target quantum state.…”

Section: Introductionmentioning

confidence: 99%

Optical preparation of H2 rovibrational levels with almost complete population transfer

Dong

Mukherjee

Zare

2013

The Journal of Chemical Physics

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Using stimulated Raman adiabatic passage (SARP), it is possible, in principle, to transfer all the population in a rovibrational level of an isolated diatomic molecule to an excited rovibrational level. We use an overlapping sequence of pump (532 nm) and dump (683 nm) single-mode laser pulses of unequal fluence to prepare isolated H2 molecules in a molecular beam. In a first series of experiments we were able to transfer more than half the population to an excited rovibrational level [N. Mukherjee, W. R. Dong, J. A. Harrison, and R. N. Zare, J. Chem. Phys. 138(5), 051101-1-051101-4 (2013)]. Since then, we have achieved almost complete transfer (97% ± 7%) of population from the H2 (v = 0, J = 0) ground rovibrational level to the H2 (v = 1, J = 0) excited rovibrational level. An explanation is presented of the SARP process and how these results are obtained.

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Section: Introductionmentioning

confidence: 99%

Optical preparation of H2 rovibrational levels with almost complete population transfer

Dong

Mukherjee

Zare

2013

The Journal of Chemical Physics

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“…The ab initio theory predicted energy transfer (and hence the electron transfer) is completely suppressed for O-end collisions [19]. In order to test the assumptions underlying this theory, we were led to consider means for producing oriented samples of NO in high vibrational states using stimulated emission pumping [20,21] with variable kinetic energies between about 30 and 1000 meV. The reason we targeted this range of translational energies of incidence -steering effects -is itself informative to the consideration of orientation experiments.…”

Section: Introductionmentioning

confidence: 99%

Orienting polar molecules without hexapoles: Optical state selection with adiabatic orientation

Schäfer

Bartels

Hocke

et al. 2012

Chemical Physics Letters

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A pedagogic review of technology used to orient polar molecules is presented to place in context the report of a new approach to this problem. Laboratory frame orientation of polar molecules is achieved by state-specific optical pumping in a region free of electric fields followed by adiabatic transport into a static electric field. This approach overcomes some of the limitations of the more common hexapole focusing method. In particular the method is nearly insensitive to the kinetic energy of the sample. We demonstrate production of oriented samples of NO (l el = 0.15 D) with translational energies above 1 eV in both high-and low-field seeking states. The method can be extended to many other classes of molecules, including near symmetric tops and ions.

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“…The local thermodynamic equilibrium (LTE) assumption, generally adopted in atmospheric models, has proved inadequate in the interpretation of certain atmospheric events (Slanger et al, 1988). Non-LTE phenomena have been recognized to take place in some stratospheric regions, where ultraviolet photodissociation generates highly energized and nonequilibrated species, because the collisions are not frequent enough to ensure thermalization of the quantum-state distribution (Yang et al, 1993). Furthermore, electronically excited species are known to be generated as well by naturally occurring phenomena such as UV-photolytic dissociation and electric discharges.…”

Section: Positive-ion Chemistry Of Ozonementioning

confidence: 99%

“…Actually, the production of N 2 O from atmospheric corona discharges has been demonstrated by field measurements and laboratory studies, and reactions of excited N 2 (A 3 S) with O 2 has been invoked, although not unequivocally demonstrated (Zipf, 1980;Hill, Rinker, & Coucouvinos, 1984;Brandvold, Martinez, & Hipsh, 1996). However, the sequence of excitation, dissociation, and ionization events that occur in such environments is likely to produce significant amounts of O 3 þ , even in nonequilibrated states, and slow or endothermic reactions can be observed (Yang et al, 1993). Inspection of Figure 2 shows, for example, that thermal reactant ions could not evolve into the products, because of the comparable heights of the barrier between 3 and 4, and of the threshold to back-dissociation, also consistent with a recent study showing that reaction (13) is slow from 100 to 298 K .…”

Section: Links Between Neutral and Ionic Atmospheric Chemistrymentioning

confidence: 99%

“…The utmost importance of accurately reproducing the measured ozone altitude profile has led over the years to an active search for novel O 3 sources, and even to predict future trends and scenarios. Moreover, the failure of modeling studies to simulate the stratospheric chemistry has also raised the suspicion that some underlying assumptions could have been wrong (Slanger et al, 1988;Yang et al, 1993). Indeed, all of the proposed mechanisms of ozone production [i.e., the O 2 þ O 2 , OH þ O 2 , and HO 2 þ O 2 reactions (Miller et al, 1994;Varandas, 2002)] involve vibrationally excited reactants, and rely on the assumption of local thermodynamic disequilibrium conditions, that point to the inadequacy of the LTE assumption to represent some atmospheric events.…”

Section: B An Ionic Route To Omentioning

confidence: 99%

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Atmospherically relevant ion chemistry of ozone and its cation

Petris¹

2003

Mass Spectrometry Reviews

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The importance of ionic processes that occur in terrestrial, planetary, and stellar atmospheres is receiving increasing recognition. Actually, ions play important, often crucial, roles in a variety of atmospheric processes throughout the universe, and a strong link with the neutral chemistry is also apparent. In the terrestrial atmosphere, the ionic reactions are most relevant in those transient and fleeting events, e.g., lightning, coronas (in thunderstorm clouds and along power lines), where the local ion density is much higher than in unperturbed air, and the chemical systems are typically far from equilibrium. In such cases, ozone, a key molecule for the terrestrial atmosphere, is also present in high local concentrations; it is formed from O(2) by the same transient event. Accordingly, this review provides a survey of the positive ion chemistry of ozone with several of the most important "atmospheric" species: the reactions, the products, and the importance of the examined processes are discussed also in the light of the local thermodynamic disequilibrium (LTD) approach to the chemistry of transient atmospheric events. In all such studies, mass spectrometry is traditionally, and remains today, the experimental technique of choice. The novel application of mass spectrometry to the study of neutral species (NRMS), highly successful for the preparation and positive detection of long-sought, otherwise inaccessible, short-lived neutrals, makes mass spectrometry the most powerful tool now available for the study of the species and processes that are relevant to atmospheric chemistry. Selected examples of the interlink between the neutral and the ionic chemistry are also illustrated.

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Stimulated emission pumping studies of energy transfer in highly vibrationally excited molecules

Cited by 62 publications

References 9 publications

Optical preparation of H2 rovibrational levels with almost complete population transfer

Optical preparation of H2 rovibrational levels with almost complete population transfer

Orienting polar molecules without hexapoles: Optical state selection with adiabatic orientation

Atmospherically relevant ion chemistry of ozone and its cation

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