Vibrational Spectroscopy and Dynamics of the Hydrazoic and Isothiocyanic Acids in Water and Methanol

Houchins, Cassidy; Weidinger, Daniel; Owrutsky, Jeffrey C.

doi:10.1021/jp102397b

Cited by 20 publications

(23 citation statements)

References 56 publications

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“…Conversely, if such an effect were present in spite of the small change in the DOS, it could also be observed in a system with additional inhomogeneous broadening and/or strong detuning from cavity resonance. It is also unlikely that there exist vibrational transitions with dipole moments much higher than the recently studied cases of W(CO) 6 and Fe(CO) 5 . ,− Similar arguments apply to transitions to higher excitation manifolds (provided the cavity is properly tuned to account for anharmonicity) as long as the molecular DOS is much higher than the polariton DOS. Because the planar-cavity polariton DOS is bound from above by the free-space DOS in Figure , we suggest that a significant change in the reaction rates due to the polariton DOS requires that it become much higher than the free-space “photon” DOS (over a reasonably wide range of frequencies to remain robust to broadening).…”

mentioning

confidence: 84%

Negligible Effect of Vibrational Polaritons on Chemical Reaction Rates via the Density of States Pathway

Vurgaftman

Simpkins

Dunkelberger

2020

J. Phys. Chem. Lett.

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We show that the polariton density of states in planar optical cavities strongly coupled to vibrational excitations remains much lower than the density of vibrational states even at the frequency of the lower and upper polaritons under most practical circumstances. The polariton density of states is higher within a narrow window only when the inhomogeneous line width is at least an order of magnitude smaller than the Rabi splitting. Therefore, modification of reaction rates via the density-of-states pathway appears small or negligible for the scenarios reported in the literature. While the polariton density of states is bounded from above by the freespace optical density of states in dielectric cavities, it can be much higher for localized phonon polariton modes of nanoscale particles. We conclude that other potential explanations of the reported reactivity changes under vibrational strong coupling should be examined.

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mentioning

confidence: 84%

Negligible Effect of Vibrational Polaritons on Chemical Reaction Rates via the Density of States Pathway

Vurgaftman

Simpkins

Dunkelberger

2020

J. Phys. Chem. Lett.

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“…Unlike OD, vibrational lifetime (2.6 ps; average of 0−1 and 1−2 transitions) 23 of the azide band significantly increases with osmolyte (except urea) concentration (inset of Figure 4A), which reflects HN 3 's unique sensitivity to local H-bonding environment. 15,24,25 For example; its lifetime increases 2-fold in going from water to methanol.…”

Section: The Journal Of Physical Chemistry Lettersmentioning

confidence: 99%

“…15,24,25 For example; its lifetime increases 2-fold in going from water to methanol. 23 In a nanometer-sized reverse micelle, its lifetime in the interfacial region, where the availability of H-bond donor to an azide group is scarce, is significantly longer than that in the core region of bulk type water environment. 26 The increase in the lifetime with increasing osmolyte concentration clearly indicates that the NNN−H 2 O H-bond population is significantly reduced due to the change in local H-bonding environment.…”

Section: The Journal Of Physical Chemistry Lettersmentioning

confidence: 99%

Modulation of the Hydrogen Bonding Structure of Water by Renal Osmolytes

Verma

Lee

Park

et al. 2015

J. Phys. Chem. Lett.

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Osmolytes are an integral part of living organism, e.g., the kidney uses sorbitol, trimethylglycine, taurine and myo-inositol to counter the deleterious effects of urea and salt. Therefore, knowing that the osmolytes' act either directly to the protein or mediated through water is of great importance. Our experimental and computational results show that protecting osmolytes, e.g., trimethylglycine and sorbitol, significantly modulate the water H-bonding network structure, although the magnitude and spatial extent of osmolyte-induced perturbation greatly vary. In contrast, urea behaves neutrally toward local water H-bonding network. Protecting osmolytes studied here show strong concentration-dependent behaviors (vibrational frequencies and lifetimes of two different infrared (IR) probes), while denaturant does not. The H-bond donor and/or acceptor (OH/NH) in a given osmolyte molecule play a critical role in defining their action. Our findings highlight the significance of the alteration of H-bonding network of water under biologically relevant environment, often encountered in real biological systems.

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“…24 Early MD simulations noted few linear hydrogen bonds with water 25 and many arrangements of dipolar character, while more recent MD simulations of SeCN -26 found an average of 3-4 hydrogen bonds, with one of them being an axial (linear) hydrogen bond. Ultrafast infrared spectroscopy has used the ν 3 mode of pseudo-halide anions to investigate ultrafast vibrational dynamics of water and other polar solvents, 23,[27][28][29][30][31][32] concentrated ion solutions, [33][34][35] ILs, [36][37][38][39][40] supported IL membranes, 41 and colloid emulsions. 42 Furthermore, a combination of MD simulations and ultrafast infrared spectroscopy developed a spectroscopic map of SeCNin D 2 O that describes the frequency dependence of the nitrile stretch to a hydrogen bonding environment.…”

Section: Introductionmentioning

confidence: 99%

An Ultrafast Vibrational Study of Dynamical Heterogeneity in the Protic Ionic Liquid Ethyl-Ammonium Nitrate

Johnson

Parker²,

Donaldson³

et al. 2019

Preprint

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Using ultrafast two-dimensional infrared spectroscopy (2D-IR), a vibrational probe (thiocyanate, SCN-) was used to investigate the hydrogen bonding network of a molten salt (ethyl-ammonium nitrate, EAN) compared to that of H2O. The 2D-IR experiments were performed in both parallel () and perpendicular () conditions along with temperature dependence for both EAN (14-130 ˚C) and H2O (5-89 ˚C). With polarization control, the frequency fluctuation correlation function can be separated into structural and rotational components. An Arrhenius analysis lead to independent activation energies for the isotropic, and anisotropic signals, structural spectral diffusion, and rotational induced spectral diffusion. The rotational Eas were similar for both EAN and H2O suggesting that SCN- is experiencing a similar jump model, i.e. where hydrogen bond reorientation is dominated by large angular jumps stemming from molecular rotation dynamics. The frequency pre-factors, however, were different where the more rigid and vicious EAN had a slower rate. Furthermore, the 2D-IR anisotropy and vibrational relaxation rates of EAN are frequency dependent, revealing that SCN- experiences two subensembles. We suggest that the sub-ensemble with a faster rotational timescale correlates to SCN- with more, weaker hydrogen bonds, and the sub-ensemble with a slower rotational timescale correlates to SCN- with a stronger, more directional hydrogen bond.

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Vibrational Spectroscopy and Dynamics of the Hydrazoic and Isothiocyanic Acids in Water and Methanol

Cited by 20 publications

References 56 publications

Negligible Effect of Vibrational Polaritons on Chemical Reaction Rates via the Density of States Pathway

Negligible Effect of Vibrational Polaritons on Chemical Reaction Rates via the Density of States Pathway

Modulation of the Hydrogen Bonding Structure of Water by Renal Osmolytes

An Ultrafast Vibrational Study of Dynamical Heterogeneity in the Protic Ionic Liquid Ethyl-Ammonium Nitrate

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