scholarly journals Advances in Molecular Spectroscopy in Condensed Phase and Quantum Chemistry

2020 ◽  
Vol 14 (1) ◽  
pp. A0114
Author(s):  
Yukihiro Ozaki
Keyword(s):  
Quantum Chemistry ◽  
Condensed Phase ◽  
Molecular Spectroscopy

Spectroscopy

2006 ◽  
Author(s):  
Abraham Nitzan
Keyword(s):  
Condensed Phase ◽  
Molecular Spectroscopy ◽  
Fundamental Problem ◽  
Optical Transition ◽  
Energy Levels ◽  
Quantum Statistical Mechanics ◽  
Potential Surfaces ◽  
Molecular Systems ◽  
Matter Interaction ◽  
Particle Level

The interaction of light with matter provides some of the most important tools for studying structure and dynamics on the microscopic scale. Atomic and molecular spectroscopy in the low pressure gas phase probes this interaction essentially on the single particle level and yields information about energy levels, state symmetries, and intramolecular potential surfaces. Understanding environmental effects in spectroscopy is important both as a fundamental problem in quantum statistical mechanics and as a prerequisite to the intelligent use of spectroscopic tools to probe and analyze molecular interactions and processes in condensed phases. Spectroscopic observables can be categorized in several ways. We can follow a temporal profile or a frequency resolved spectrum; we may distinguish between observables that reflect linear or nonlinear response to the probe beam; we can study different energy domains and different timescales and we can look at resonant and nonresonant response. This chapter discusses some concepts, issues, and methodologies that pertain to the effect of a condensed phase environment on these observables. For an in-depth look at these issues the reader may consult many texts that focus on particular spectroscopies. With focus on the optical response of molecular systems, effects of condensed phase environments can be broadly discussed within four categories: 1. Several important effects are equilibrium in nature, for example spectral shifts associated with solvent induced changes in solute energy levels are equilibrium properties of the solvent–solute system. Obviously, such observables may themselves be associated with dynamical phenomena, in the example of solvent shifts it is the dynamics of solvation that affects their dynamical evolution. Another class of equilibrium effects on radiation– matter interaction includes properties derived from symmetry rules. A solvent can affect a change in the equilibrium configuration of a chromophore solute and consequently the associated selection rules for a given optical transition. Some optical phenomena are sensitive to the symmetry of the environment, for example, surface versus bulk geometry. 2. The environment affects the properties of the radiation field; the simplest example is the appearance of the dielectric coefficient ε in the theory of radiation–matter interaction.

Dissecting intermolecular interactions in the condensed phase of ibuprofen and related compounds: the specific role and quantification of hydrogen bonding and dispersion forces

2020 ◽  
Vol 22 (9) ◽  
pp. 4896-4904 ◽  
Author(s):  
V. N. Emel’yanenko ◽  
P. Stange ◽  
J. Feder-Kubis ◽  
S. P. Verevkin ◽  
R. Ludwig
Keyword(s):  
Hydrogen Bonding ◽  
Infrared Spectroscopy ◽  
Quantum Chemistry ◽  
Intermolecular Interactions ◽  
Condensed Phase ◽  
Specific Role ◽  
Dispersion Interaction ◽  
Dispersion Forces ◽  
Related Compounds

Hydrogen bonding and dispersion interaction in liquid ibuprofen is analyzed by thermodynamic methods, infrared spectroscopy and quantum chemistry.

On a Unified Theory of Harmonic Oscillator Two-Centre Integrals

1972 ◽  
Vol 27 (2) ◽  
pp. 180-187
Author(s):  
W Wltschel
Keyword(s):  
Quantum Chemistry ◽  
Harmonic Oscillator ◽  
Molecular Spectroscopy ◽  
Occupation Number ◽  
Operator Technique ◽  
Unified Theory ◽  
Number Representation ◽  
Molecular Physics ◽  
Operator Identity

Abstract Occupation number representation and operator-technique are used in the calculation of harmonic oscillator matrixelements for one and two centres and for equal and different frequencies. The potentials treated are generalized Gauss-potentials of the form p̑k x̑l exp{a x̑2 }, x̑k p̑l exp{a p̑2 }, and p̑k x̑l exp{a x̑ p̑} which by application of an operator identity could be reduced to the same form. Applications in nuclear and molecular physics, in molecular spectroscopy and in quantum chemistry are discussed briefly.

Chemical Dynamics in Condensed Phases

2006 ◽  
Author(s):  
Abraham Nitzan
Keyword(s):  
Complex Systems ◽  
Condensed Phase ◽  
Quantum Dynamics ◽  
Vibrational Energy ◽  
Molecular Spectroscopy ◽  
Quantum Evolution ◽  
Condensed Phases ◽  
Solvation Dynamics ◽  
Chemical Dynamics ◽  
Molecular Systems

This text provides a uniform and consistent approach to diversified problems encountered in the study of dynamical processes in condensed phase molecular systems. Given the broad interdisciplinary aspect of this subject, the book focuses on three themes: coverage of needed background material, in-depth introduction of methodologies, and analysis of several key applications. The uniform approach and common language used in all discussions help to develop general understanding and insight on condensed phases chemical dynamics. The applications discussed are among the most fundamental processes that underlie physical, chemical and biological phenomena in complex systems. The first part of the book starts with a general review of basic mathematical and physical methods (Chapter 1) and a few introductory chapters on quantum dynamics (Chapter 2), interaction of radiation and matter (Chapter 3) and basic properties of solids (chapter 4) and liquids (Chapter 5). In the second part the text embarks on a broad coverage of the main methodological approaches. The central role of classical and quantum time correlation functions is emphasized in Chapter 6. The presentation of dynamical phenomena in complex systems as stochastic processes is discussed in Chapters 7 and 8. The basic theory of quantum relaxation phenomena is developed in Chapter 9, and carried on in Chapter 10 which introduces the density operator, its quantum evolution in Liouville space, and the concept of reduced equation of motions. The methodological part concludes with a discussion of linear response theory in Chapter 11, and of the spin-boson model in chapter 12. The third part of the book applies the methodologies introduced earlier to several fundamental processes that underlie much of the dynamical behaviour of condensed phase molecular systems. Vibrational relaxation and vibrational energy transfer (Chapter 13), Barrier crossing and diffusion controlled reactions (Chapter 14), solvation dynamics (Chapter 15), electron transfer in bulk solvents (Chapter 16) and at electrodes/electrolyte and metal/molecule/metal junctions (Chapter 17), and several processes pertaining to molecular spectroscopy in condensed phases (Chapter 18) are the main subjects discussed in this part.

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