Spectral response of crystalline acetanilide and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>N</mml:mi></mml:mrow></mml:math>-methylacetamide: Vibrational self-trapping in hydrogen-bonded crystals

Edler, Julian; Hamm, Peter

doi:10.1103/physrevb.69.214301

Cited by 63 publications

(49 citation statements)

References 51 publications

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“…Difference between the vibration intensity of (R,S)-atenolol spectra at −170 • C before and after deuteration in the C-H stretch vibration region. Likewise, N-methylacetamide presents non-fundamental vibration bands at 2900-2650 cm −1 interpreted as Fermi resonances with the overtone and combination modes of amide bands [15].…”

Section: Infrared Spectra Of S-and (Rs)-atenolol In Solid Statementioning

confidence: 99%

Infrared spectroscopy of racemic and enantiomeric forms of atenolol

Castro

Canotilho

Barbosa

et al. 2007

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

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The molecular structure of conformational isomorphs given by X-ray diffraction for racemic and enantiomeric atenolol were optimized at the HF/6-31G* level of theory and the infrared spectra of the structure were calculated. These spectra are used to characterize the differences between the various atenolol conformers.The spectra of the (R,S)-and S-atenolol solid forms were recorded and the bands corresponding to the functional groups identified with the aid of the calculated spectra, fitting analysis, temperature effect and H/D isotopic exchange. Particular attention was paid to the stretch vibration modes of the functional groups present in the atenolol.

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Section: Infrared Spectra Of S-and (Rs)-atenolol In Solid Statementioning

confidence: 99%

Infrared spectroscopy of racemic and enantiomeric forms of atenolol

Castro

Canotilho

Barbosa

et al. 2007

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

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“…The nonlinear pump-probe response of these infrared (IR) transitions, in turn, often decays on an ultrafast (a few 100 fs) time scale [13][14][15] and in some cases also exhibits complex oscillatory features. [6][7][8][9][10][11][12] It is the very anharmonic nature of the hydrogen bond potentials that gives rise to the peculiar vibrational spectroscopy, [16][17][18][19][20][21][22] i.e., in essence the fact that the typical dissociation energy of a hydrogen bond is in the same range as the frequency of its vibrational modes. It has also been shown that the problem is inherently high-dimensional, [17][18][19][20][21][22] which renders the modeling of the quantum dynamics demanding and the interpretation of the computational results complicated.…”

Section: Introductionmentioning

confidence: 99%

“…The prototype example is the OH-stretch vibration of liquid water, where both broadening and solvation shift are a few 100 cm −1 , as opposed to typically 10 cm −1 of "normal" vibrational modes. Furthermore, if a hydrogen bond is of intramolecular nature, [6][7][8] binding a dimer with reasonably well defined structure, 9,10 or in hydrogen-bonded molecular crystals, 11,12 the vibrational band often contains a pronounced substructure. The nonlinear pump-probe response of these infrared (IR) transitions, in turn, often decays on an ultrafast (a few 100 fs) time scale [13][14][15] and in some cases also exhibits complex oscillatory features.…”

Section: Introductionmentioning

confidence: 99%

Nonadiabatic vibrational dynamics in the HCO2−⋅H2O complex

Hamm

Stock

2015

The Journal of Chemical Physics

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Based on extensive ab initio calculations and the time-propagation of the nuclear Schrödinger equation, we study the vibrational relaxation dynamics and resulting spectral signatures of the OH stretch vibration of a hydrogen-bonded complex, HCO − 2 H 2 O. Despite their smallness, it has been shown experimentally by Johnson and coworkers that the gas-phase infrared spectra of these types of complexes exhibit much of the complexity commonly observed for hydrogen-bonded systems. That is, the OH stretch band exhibits a significant red shift together with an extreme broadening and a pronounced substructure, which reflects its very strong anharmonicity. Employing an adiabatic separation of time scales between the three intramolecular high-frequency modes of the water molecule and the three most important intermolecular low-frequency modes of the complex, we calculate potential energy surfaces (PESs) of the ground and the first excited states of the high-frequency modes and identify a vibrational conical intersection between the PESs of the OH stretch fundamental and the HOH bend overtone. By performing a time-dependent propagation of the resulting system, we show that the conical intersection affects a coherent population transfer between the two states, the first step of which being ultrafast (60 fs) and irreversible. The subsequent relaxation of vibrational energy into the HOH bend and ground state occurs incoherently but also quite fast (1 ps), although the corresponding PESs are well separated in energy. Owing to the smaller effective mass difference between light and heavy degrees of freedom, the adiabatic ansatz is consequently less significant for vibrations than in the electronic case. Based on the model, we consider several approximations to calculate the measured Ar-tag action spectrum of HCO − 2 H 2 O and achieve semiquantitative agreement with the experiment. Based on extensive ab initio calculations and the time-propagation of the nuclear Schrödinger equation, we study the vibrational relaxation dynamics and resulting spectral signatures of the OH stretch vibration of a hydrogen-bonded complex, HCO − 2 · H 2 O. Despite their smallness, it has been shown experimentally by Johnson and coworkers that the gas-phase infrared spectra of these types of complexes exhibit much of the complexity commonly observed for hydrogen-bonded systems. That is, the OH stretch band exhibits a significant red shift together with an extreme broadening and a pronounced substructure, which reflects its very strong anharmonicity. Employing an adiabatic separation of time scales between the three intramolecular high-frequency modes of the water molecule and the three most important intermolecular low-frequency modes of the complex, we calculate potential energy surfaces (PESs) of the ground and the first excited states of the high-frequency modes and identify a vibrational conical intersection between the PESs of the OH stretch fundamental and the HOH bend overtone. By performing a time-dependent propagation of the resulti...

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“…The observation of transitions, spectroscopic frequency shifts or relaxation times of spectral elements were connected to spatial localization by theoretical or numerical analysis not by direct observation as with macroscopic systems. The atomic systems included the analysis of resonant Raman spectra in the highly nonlinear halide-bridged mixed-valence transition metal complex [Pt(en) 2 ][Pt(en) 2 Cl 2 ](ClO 4 ) 4 [47], the anomalous optic mode found with neutron scattering in the monatomic bcc crystal of 4 He [48], the localized 1-D mode identified in alpha uranium [49], and the spectral anomalies interpreted as a signature of vibrational self trapping in hydrogen-bonded acetanilide [50,51]. The temperature dependence of the resonances in KI:Ag + , a theme in this paper, is another thermal equilibrium example.…”

Section: Two Elastic Configurations In Ki:ag + Without Ilmsmentioning

confidence: 99%

Shozo Takeno and intrinsic localized modes

Sievers

2012

NOLTA

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Abstract:Research into defect lattice dynamics played an important roll in the development of our work on the local mode properties of anharmonic lattices. Using a historical perspective I show that the different theoretical and experimental studies of the impurity-induced absorption associated with the low frequency resonances in alkali halide crystals provided the kernel for our breakout into a new area.Key Words: defect induced absorption, anharmonicity, intrinsic localized modes, two elastic configurations 1. Some research at the laboratory of atomic and solid state physics in 1965When Shozo Takeno arrived at Cornell in 1965 the properties of localized vibrational modes in the acoustic spectrum of ionic crystals were being uncovered and represented one of the main laboratory thrusts. The experimental discovery by Schaefer in 1958 that a hydrogen ion substituted into a KCl crystal generated a sharp IR absorption line associated with a vibrational mode far above the plane wave phonon spectrum [1] illuminated the pathway for experimentalists to enter a field where there had been a great deal of theoretical work over the years but no experiments. This mode was strongly localized in space because of its large frequency separation from the plane wave spectrum, a result expected from the dynamical theory of lattices [2,3]. It quickly became apparent that there were very few different kinds of impurities that produced local modes so attention turned to the question of how impurities might alter the acoustic spectrum. Thermal conductivity was the experimental probe of choice at Cornell since theory suggested that impurities would scatter acoustic waves. By measuring the temperature dependence of the thermal conductivity over a large temperature interval it was discovered that, in addition to the expected Rayleigh-type scattering from the impurities, there was another contribution indicating the presence of a phonon active impurity mode that produced resonance scattering in some defect-lattice combinations [4]. Since it had been assumed that such resonances observed in the thermal conductivity temperature dependence were not IR active a complete surprise occurred when, with a far infrared (FIR) spectroscopic technique, it was discovered that KI:Ag + had a sharp absorption line at 17.3 cm −1 , far down in the acoustic spectrum [5]. Unlike the H − ion impurity mode found by Schaefer this impurity-induced vibration was in direct contact with the crystal phonon modes and such resonant 2

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Spectral response of crystalline acetanilide andN-methylacetamide: Vibrational self-trapping in hydrogen-bonded crystals

Cited by 63 publications

References 51 publications

Infrared spectroscopy of racemic and enantiomeric forms of atenolol

Infrared spectroscopy of racemic and enantiomeric forms of atenolol

Nonadiabatic vibrational dynamics in the HCO2−⋅H2O complex

Shozo Takeno and intrinsic localized modes

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