High-resolution CO-laser sideband spectrometer for molecular-beam optothermal spectroscopy in the 5–6.6 μm wavelength region

Merker, U.; Engels, Peter; Madeja, Frank; Havenith, Martina; Urban, W.

doi:10.1063/1.1149691

Cited by 30 publications

(23 citation statements)

References 51 publications

(50 reference statements)

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“…These range from low resolution studies 28 using mostly cavity ringdown techniques 22,49,50 over medium resolution Fourier transform infrared ͑FTIR͒ spectra 21 and action spectra 25 to very high resolution analyses including tunneling splittings. 5,30,51,52 Typically, the focus was on the C -H / O-H/ C=O/ C-O valence vibrations and on some of their isotopic variants. The O-H stretching dynamics turned out to be particularly challenging 21,22,50 due to interactions with combination bands from the lower frequency range.…”

Section: Introductionmentioning

confidence: 99%

Probing the stiffness of the simplest double hydrogen bond: The symmetric hydrogen bond modes of jet-cooled formic acid dimer

Xue

Suhm

2009

The Journal of Chemical Physics

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Formic acid dimer is held together and kept planar by two strong hydrogen bonds, which give rise to intermolecular vibrations. Raman active fundamentals, overtones, and combination bands involving out-of-plane bending and stretching vibrations of the hydrogen bonds are recorded under jet-cooled, vacuum-isolated conditions between 100 and 750 cm−1 and assigned with the help of isotope substitution. Individual anharmonicity effects are shown to be very small (xi,j=−(1±2) cm−1), where they are accessible by experiment. However, they may accumulate to substantial differences between harmonic and anharmonic fundamental excitations. Preliminary experimental evidence for the most elusive fundamental vibration of formic acid dimer, symmetric OH torsion, is presented. A rigorous experimental reference frame for existing and future high level quantum chemical and dynamical treatments of this important prototype system is provided. The effects of clustering beyond the dimer on the low frequency dynamics are found to be small, whereas argon coating gives rise to blueshifts.

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Section: Introductionmentioning

confidence: 99%

Probing the stiffness of the simplest double hydrogen bond: The symmetric hydrogen bond modes of jet-cooled formic acid dimer

Xue

Suhm

2009

The Journal of Chemical Physics

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“…Our tunable liquid nitrogen cooled, sealed-off CO-laser 35,36 covers the carbonyl (CQO) stretch and the amide bands which contain important structural information of proteins. The gas laser is line tuneable with approximately 100 laser lines between 1600 and 2000 cm À1 (5-6 mm).…”

Section: Light Sourcesmentioning

confidence: 99%

SNIM: Scanning near-field infrared microscopy

Bründermann

Havenith

2008

Annu. Rep. Prog. Chem., Sect. C: Phys. Chem.

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“…One vibrational band at 1740 cm -1 was reported for the C = O asymmetric stretch of FAD. Later, a high resolution study yielded two separate vibrational bands centered at 1738.5 and 1741.5 cm -1 [52]. However, the high density of lines did not allow a definitive assignment in this frequency range.…”

Section: Infrared Vibrational Spectroscopymentioning

confidence: 99%

Coherent Proton Tunneling in Hydrogen Bonds of Isolated Molecules: Carboxylic Dimers

Havenith¹

2006

Hydrogen‐Transfer Reactions

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IntroductionDue to the exceptional importance of hydrogen bonds in biology and chemistry the detailed investigation of their structure and dynamics has attracted the attention of several experimental and theoretical groups. Laser spectroscopic measurements and quantum mechanical calculations have led, in recent years, to remarkable progress towards the detailed understanding of important prototype systems such as (NH 3 ) 2 [1], (H 2 O) 2 [2], and DNA base pairs [3].Double hydrogen bonded systems play a crucial role in that they serve as model systems for the understanding of DNA base pairs. Proton transfer is of fundamental interest for biology as well as being a fundamental reaction in chemistry [4,5]. Moreover, multiple-proton transfer in hydrogen bonded systems is one of the most fundamental processes in biology and chemistry. It governs oxidationreduction reactions in many chemical and biological reactions [6]. In proton pumping mechanisms of trans membrane proteins protons are transported across the membrane by subsequent proton transfer. These reactions may incorporate strong quantum effects due to the low mass of the proton. The observation of pronounced isotopic effects is taken as an indication of a strong tunneling contribution. In contrast, the classical transmission probability is zero as long as the energy of the particle is lower than the barrier height (V ‡ ) and is equal to 1 if the energy (E) exceeds this. For an ensemble at temperature T this leads to the well known Arrhenius equation for the reaction rate which is proportional to exp (-(E -V ‡ )/ kT). The transmission will, therefore, depend solely on the barrier height and not on the width or on the exact shape of the transition barrier. Isotopic substitution will shift the zero point energies relative to the transition barrier and will, therefore, lead to a change in the reaction constant.Quantum mechanical tunneling is a result of the wavelike nature of particles which allows transmission through a reaction barrier. The quantum mechanical transmission probability for energies below V ‡ is governed by tunneling and reflection at the barrier. The transmission is larger than zero even well below the barrier and will depend crucially on the barrier width. In Hydrogen-Transfer Reactions. Edited by

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High-resolution CO-laser sideband spectrometer for molecular-beam optothermal spectroscopy in the 5–6.6 μm wavelength region

Cited by 30 publications

References 51 publications

Probing the stiffness of the simplest double hydrogen bond: The symmetric hydrogen bond modes of jet-cooled formic acid dimer

Probing the stiffness of the simplest double hydrogen bond: The symmetric hydrogen bond modes of jet-cooled formic acid dimer

SNIM: Scanning near-field infrared microscopy

Coherent Proton Tunneling in Hydrogen Bonds of Isolated Molecules: Carboxylic Dimers

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