Vibrational energy levels and vibronic structure of electronic spectra in molecules with large amplitude motions

Abstract An expression for the Hamiltonian H(ρ1, ρ2, ρ3) of a vibrating-rotating triatomic molecule is derived using three curvilinear coordinates gi, Q 3 in such a way that the Hamiltonian obtained is applicable to any bent triatomic molecule and allows for large displacements in all the three modes of motion. A variational technique is then used to calculate the low lying vibrational energy levels (υ1, υ2, υ3) of the H2O molecule in its X̃1A1 ground state. The kinetic energy of the Hamiltonian T(ρ1, ρ2, ρ3) takes into account the large amplitude character of the three modes together with their interaction. But in order to minimize the formidable amount of computation, a simple quadratic potential F(ρ1, ρ2, ρ3) is assumed for all the three modes which only serves to illustrate the method of calculation.

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Ab Initio Study of the Large Amplitude Motions of Various Monosubstituted Isotopologues of Methylamine (CH3-NH2)

Frontiers in Chemistry ◽

10.3389/fchem.2021.751203 ◽

2021 ◽

Vol 9 ◽

Author(s):

Muneerah Mogren Al-Mogren ◽

María Luisa Senent

Keyword(s):

Large Amplitude ◽

Vibrational Energy ◽

Energy Levels ◽

Three Dimensional ◽

Far Infrared ◽

Infrared Region ◽

Strong Interactions ◽

Three Dimensional Model ◽

Large Amplitude Motions ◽

Centrifugal Distortion Constants

CCSD(T)-F12 theory is applied to determine electronic ground state spectroscopic parameters of various isotopologues of methylamine (CH3-NH2) containing cosmological abundant elements, such as D, 13C and 15N. Special attention is given to the far infrared region. The studied isotopologues can be classified in the G12, G6 and G4 molecular symmetry groups. The rotational and centrifugal distortion constants and the anharmonic fundamentals are determined using second order perturbation theory. Fermi displacements of the vibrational bands are predicted. The low vibrational energy levels corresponding to the large amplitude motions are determine variationally using a flexible three-dimensional model depending on the NH2 bending and wagging and the CH3 torsional coordinates. The model has been defined assuming that, in the amine group, the bending and the wagging modes interact strongly. The vibrational levels split into six components corresponding to the six minima of the potential energy surface. The accuracy of the kinetic energy parameters has an important effect on the energies. Strong interactions among the large amplitude motions are observed. Isotopic effects are relevant for the deuterated species.

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INVERSION VIBRATIONAL ENERGY LEVELS OF AsH3 + STUDIED BY ZERO-KINETIC-ENERGY PHOTOELECTRON SPECTROSCOPY

Proceedings of the 71st International Symposium on Molecular Spectroscopy ◽

10.15278/isms.2016.tf09 ◽

2016 ◽

Author(s):

Yuxiang Mo

Keyword(s):

Kinetic Energy ◽

Photoelectron Spectroscopy ◽

Vibrational Energy ◽

Energy Levels ◽

Zero Kinetic Energy ◽

Vibrational Energy Levels

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Research progress in the effects of terahertz waves on biomacromolecules

Military Medical Research ◽

10.1186/s40779-021-00321-8 ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Liu Sun ◽

Li Zhao ◽

Rui-Yun Peng

Keyword(s):

Vibrational Energy ◽

Rapid Development ◽

Energy Levels ◽

Basic Research ◽

Research Progress ◽

Biological Macromolecules ◽

Terahertz Waves ◽

Terahertz Spectrum ◽

Biomedical Field ◽

Vibrational Energy Levels

AbstractWith the rapid development of terahertz technologies, basic research and applications of terahertz waves in biomedicine have attracted increasing attention. The rotation and vibrational energy levels of biomacromolecules fall in the energy range of terahertz waves; thus, terahertz waves might interact with biomacromolecules. Therefore, terahertz waves have been widely applied to explore features of the terahertz spectrum of biomacromolecules. However, the effects of terahertz waves on biomacromolecules are largely unexplored. Although some progress has been reported, there are still numerous technical barriers to clarifying the relation between terahertz waves and biomacromolecules and to realizing the accurate regulation of biological macromolecules by terahertz waves. Therefore, further investigations should be conducted in the future. In this paper, we reviewed terahertz waves and their biomedical research advantages, applications of terahertz waves on biomacromolecules and the effects of terahertz waves on biomacromolecules. These findings will provide novel ideas and methods for the research and application of terahertz waves in the biomedical field.

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MARVEL: measured active rotational–vibrational energy levels

Journal of Molecular Spectroscopy ◽

10.1016/j.jms.2007.07.005 ◽

2007 ◽

Vol 245 (2) ◽

pp. 115-125 ◽

Cited By ~ 133

Author(s):

Tibor Furtenbacher ◽

Attila G. Császár ◽

Jonathan Tennyson

Keyword(s):

Vibrational Energy ◽

Energy Levels ◽

Vibrational Energy Levels

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Vibrational band-structures caused by internal rotations of the boron Wankel rotor B11−

RSC Advances ◽

10.1039/d0ra08821h ◽

2021 ◽

Vol 11 (6) ◽

pp. 3613-3621

Author(s):

Yonghong Xu ◽

Huihui Wang ◽

Yonggang Yang ◽

Changyong Li ◽

Liantuan Xiao ◽

...

Keyword(s):

Vibrational Energy ◽

Energy Levels ◽

Vibrational Band ◽

Spectral Broadening ◽

Band Structures ◽

Internal Rotations ◽

Vibrational Energy Levels

The band structures of the vibrational energy levels of B11− lead to corresponding spectral broadening. The vibrational band-structures of planar boron rotors are caused by internal rotations.

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