Infrared and Raman Spectra of Polyatomic Molecules.

Herzberg, G.; Crawford, Bryce

doi:10.1021/j150447a021

Cited by 1,727 publications

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“…The n 2 (a 1 ) mode of ammonia (at 950 cm−1 in the gas phase [23]) is very sensitive to the acid strength of the oxide to which it is 4. Discussion coordinated: the greater the electron-acceptor power, the greater the shift of n 2 to higher frequenThe Auger spectroscopic data of Fig.…”

Section: Introductionmentioning

confidence: 99%

An infrared spectroscopic investigation of thin alumina films: measurement of acid sites and surface reactivity

Kaltchev

1999

Surface Science

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The surface chemical activity of an alumina films grown on Mo(100) by oxidation of aluminum evaporated onto the surface and oxidized using water is examined using Auger, X-ray photoelectron and reflection/absorption infrared spectroscopies. The formation of alumina is confirmed using Auger and X-ray photoelectron spectroscopy from the positions and intensities of the aluminum features and using reflection-absorption infrared spectroscopy from the longitudinal optical modes of the Al-O bonds measured at~935 cm−1. The presence of surface hydroxyls is monitored by forming films using D 2 O which are evidenced by a feature at~2700 cm−1. Ammonia adsorption on a dehydroxylated surface yields a single peak at 1260 cm−1 due to ammonia adsorbed at a surface Lewis site where the principle symmetry axis of ammonia is oriented perpendicularly to the surface plane. Ammonia also appears to adsorb at Lewis sites on a hydroxylated surface with a slightly different adsorption geometry from that on a dehydroxylated surface. Finally, the chemistry of trimethyl aluminum adsorbed on the planar hydroxylated alumina surface is compared with that found on high-surface-area c-alumina where the spectra and the chemistry found in both régimes is exactly identical except that the low-frequency methyl bending modes (at 769 and 718 cm−1) are not obscured on the thin film by the intense substrate whereas they are on the high-surface-area support.

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Section: Introductionmentioning

confidence: 99%

An infrared spectroscopic investigation of thin alumina films: measurement of acid sites and surface reactivity

Kaltchev

1999

Surface Science

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“…As is known [18,19], one of the forms of internal motion in polyatomic molecules is torsion oscillation which for sufficiently large amplitudes transforms to rotational motion.…”

Section: The Physical Problems Are Reduced To Quantum Pendulummentioning

confidence: 99%

“…Equilibrium configurations (transconfigurations) are obtained by rotating of the angles π 3 , π 3 + 2π 3 , π 3 + 2 2π 3 . Below we give the numerical values [18,19] of other parameters of some organic molecules having the property of internal rotation. Thus for the molecule of ethane C 2 H 6 we have The Schrodinger equation corresponding to Hamiltonian (7) has the form…”

Section: The Physical Problems Are Reduced To Quantum Pendulummentioning

confidence: 99%

Quantum chaos and its kinetic stage of evolution

Chotorlishvili

Ugulava

2010

Physica D: Nonlinear Phenomena

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Usually reason of irreversibility in open quantum-mechanical system is interaction with a thermal bath, consisting form infinite number of degrees of freedom. Irreversibility in the system appears due to the averaging over all possible realizations of the environment states. But, in case of open quantum-mechanical system with few degrees of freedom situation is much more complicated.Should one still expect irreversibility, if external perturbation is just an adiabatic force without any random features? Problem is not clear yet. This is main question we address in this review paper. We prove that key point in the formation of irreversibility in chaotic quantum-mechanical systems with few degrees of freedom, is the complicated structure of energy spectrum. We shall consider quantum mechanical-system with parametrically dependent energy spectrum. In particular, we study energy spectrum of the Mathieu-Schrodinger equation. Structure of the spectrum is quite non-trivial, consists from the domains of non-degenerated and degenerated stats, separated from each other by branch points. Due to the modulation of the parameter, system will perform transitions from one domain to other one. For determination of eigenstates for each domain and transition probabilities between them, we utilize methods of abstract algebra. We shall show that peculiarity of parametrical dependence of energy terms, leads to the formation of mixed state and to the irreversibility, even for small number of levels involved into the process. This last statement is important. Meaning is that, we are going to investigate quantum chaos in essentially quantum domain.In the second part of the paper, we will introduce concept of random quantum phase approximation. Then along with the methods of random matrix theory, we will use this assumption, for derivation of muster equation in the formal and mathematically strict way.

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“…In order to explain the observed isotopic dependence of this spectral line it is necessary to introduce a Jahn-Teller interaction with a LVM. The vibrational modes of a tetrahedral molecule (MX 4 ) are classified [26] according to the irreducible representations of T d as Γ 1 + Γ 3 + 2Γ 5 using standard notation [27]. As we shall see, only the Γ 5 modes can give rise to a mass dependence of the zero-phonon line.…”

Section: Theoretical Formalismmentioning

confidence: 99%

Isotope splitting of the zero-phonon line of Fe2+ in cubic III–V semiconductors

Colignon

Mailleux

Kartheuser

et al. 1998

Solid State Communications

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A theoretical study of the isotopic-mass dependence of the internal transitions of Fe 2+ at a cation site in a cubic zinc-blende semiconductor is presented. The model used is based on crystal-field theory and includes the spinorbit interaction and a weak dynamic Jahn-Teller coupling between the 5 Γ 5 excited manifold of Fe 2+ and a local vibrational mode (LVM) of Γ 5 symmetry. The mass dependence of the LVM frequency is described, in the harmonic approximation, within two different limits: the rigid-cage model and a molecular model. In the rigidcage model, the Fe 2+ ion undergoes a displacement but the rest of the lattice is fixed. In this case, a simple M -1l2 dependence of the frequency is obtained and the Jahn-Teller energy, E JT is independent of the mass. In the molecular model, the four nearest neighbors of the magnetic ion are allowed to move and the LVM then behaves as the Γ 5 mode of a MX 4 tetrahedral molecule leading to a more complicated dependence of the frequency on the isotopic mass and to a mass-dependence of E JT . The theoretical results obtained with these two models are compared with the observed isotopic shifts of the zero-phonon lines in InP:Fe and GaP:Fe corresponding to an optical transition between the vibronic Γ 1 ground state and the lowest Γ 5 state originating from the 5 Γ 5 excited orbital multiplet. A prediction of the isotopic shifts of the zero-phonon line in GaAs:Fe is also presented.

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Infrared and Raman Spectra of Polyatomic Molecules.

Cited by 1,727 publications

References 0 publications

An infrared spectroscopic investigation of thin alumina films: measurement of acid sites and surface reactivity

An infrared spectroscopic investigation of thin alumina films: measurement of acid sites and surface reactivity

Quantum chaos and its kinetic stage of evolution

Isotope splitting of the zero-phonon line of Fe2+ in cubic III–V semiconductors

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