Lecture

Molecular Energy Levels

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In course

CH-448: Photomedicine

The most important clinical diagnostic and therapeutic applications of light will be described. In addition, this course will address the principles governing the interactions between light and biological tissues, their optical properties and basic concept ...

Description

This lecture explores the different energy levels of molecules, including electronic, vibrational, rotational, and translational energy. It delves into the quantization of energy levels, molecular orbitals, and electronic transitions. The discussion extends to the applications of optical spectroscopy in photomedicine, such as absorption and fluorescence spectroscopies, and the population of energy levels based on Boltzmann's distribution.

Instructor

Georges Wagnières

Georges Wagnières received his diploma degree (MSc) in physics from the University of Lausanne, Switzerland, in 1986. He obtained his doctorate in science (PhD) in physics (Biomedical optics) from the Swiss Federal Institute of Technology at Lausanne (EPFL) in 1992 and did a postdoctoral work in the Wellman Laboratories of Photomedicine (Harvard Medical School), Boston, USA, from 1993 to 1994. He also obtained a Master degree in Management of Technology delivered by the Ecole des Hautes Etudes Commerciales (HEC) of Lausanne University and the EPFL in 2001. Georges Wagnières manages a research group active in the fields of: - Detection of early superficial cancers by fluorescence imaging. - Characterization of early superficial cancers by high magnification narrow band imaging. - In vivo and in vitro measurement of the vascular and tissular oxygen concentration by time-resolved luminescence spectroscopy and imaging. - Preclinical and clinical study of new photosensitizers for photodynamic therapy (PDT). - Treatment of neurodegenerative conditions (Alzheimer, Parkinson's diseases) by photobiomodulation. - Preclinical and clinical photodynamic therapy of inflammatory bowel diseases and atheroscerotic plaque. - Improvement of the selective vascular extravasation of chemotherapeutic agents by PDT. - Monitoring the light dosimetry during PDT by fluorescence spectroscopy and imaging. - Monitoring laser treatments of the retina by reflectance imaging. - Light dosimetry and tissue optical spectroscopy. - Radiometry. - Development of light delivery systems for biomedical applications. Georges Wagnières is also co-founder and was chairman of one spin-off companies: - Medlight SA, founded in July 1997, which develops, produces and commercializes light distributors for photodynamic therapy. Georges Wagnières has currently authored more than 235 papers (more than 150 in international journals with review board) and is inventor of 18 patents. He supervised 12 PhD students up to now, and currently teaches biomedical optics and photomedicine in master programs and doctoral schools. In addition, he gives the course entitled "Physique Générale I" to biology first year students registered to the Biology School of the Lausanne's University. MAIN PUBLICATIONS Please visit: https://www.epfl.ch/labs/lifmet/wagnieres/publications/

Official source

Ontological neighbourhood

Chemistry

Physical chemistry: Spectroscopy

Related concepts (32)

Molecular orbital

In chemistry, a molecular orbital (ɒrbədl) is a mathematical function describing the location and wave-like behavior of an electron in a molecule. This function can be used to calculate chemical and physical properties such as the probability of finding an electron in any specific region. The terms atomic orbital and molecular orbital were introduced by Robert S. Mulliken in 1932 to mean one-electron orbital wave functions. At an elementary level, they are used to describe the region of space in which a function has a significant amplitude.

Absorption spectroscopy

Absorption spectroscopy refers to spectroscopic techniques that measure the absorption of electromagnetic radiation, as a function of frequency or wavelength, due to its interaction with a sample. The sample absorbs energy, i.e., photons, from the radiating field. The intensity of the absorption varies as a function of frequency, and this variation is the absorption spectrum. Absorption spectroscopy is performed across the electromagnetic spectrum.

Molecular orbital theory

In chemistry, molecular orbital theory (MO theory or MOT) is a method for describing the electronic structure of molecules using quantum mechanics. It was proposed early in the 20th century. In molecular orbital theory, electrons in a molecule are not assigned to individual chemical bonds between atoms, but are treated as moving under the influence of the atomic nuclei in the whole molecule. Quantum mechanics describes the spatial and energetic properties of electrons as molecular orbitals that surround two or more atoms in a molecule and contain valence electrons between atoms.

Atomic absorption spectroscopy

Atomic absorption spectroscopy (AAS) and atomic emission spectroscopy (AES) is a spectroanalytical procedure for the quantitative determination of chemical elements by free atoms in the gaseous state. Atomic absorption spectroscopy is based on absorption of light by free metallic ions. In analytical chemistry the technique is used for determining the concentration of a particular element (the analyte) in a sample to be analyzed.

Raman spectroscopy

Raman spectroscopy (ˈrɑːmən) (named after Indian physicist C. V. Raman) is a spectroscopic technique typically used to determine vibrational modes of molecules, although rotational and other low-frequency modes of systems may also be observed. Raman spectroscopy is commonly used in chemistry to provide a structural fingerprint by which molecules can be identified. Raman spectroscopy relies upon inelastic scattering of photons, known as Raman scattering.

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