Related Experiment Video
Updated: Jun 25, 2026

High-definition Fourier Transform Infrared (FT-IR) Spectroscopic Imaging of Human Tissue Sections towards Improving Pathology
Published on: January 21, 2015
Intensity tracking for theoretical infrared spectroscopy of large molecules
Sandra Luber1, Johannes Neugebauer, Markus Reiher
1Laboratorium für Physikalische Chemie, ETH Zürich, Switzerland.
Abstract:
We present an approach for the direct calculation of vibrational normal modes with high infrared intensities based on a mode-tracking-like algorithm [M. Reiher and J. Neugebauer, J. Chem. Phys. 118, 1634 (2003)] but with distinct features: no collective guess vibration is utilized but high-intensity distortions are constructed. Only the modes of interest with the highest infrared intensities are then targeted irrespective of a predefinition of the underlying collective normal coordinates. This leads to a fast access to the most important features in infrared spectra. The different implementations of the mode selection procedure are validated on a set of small organic molecules as well as on the metal complex Delta(deltadeltadelta)-tris(ethylenediaminato)cobalt(III) and the peptide all-(S)-decaalanine. As a critical test case, approximate infrared spectra of Schrock's dinitrogen molybdenum complex are calculated via intensity tracking.
Related Concept Videos
IR Spectroscopy: Molecular Vibration Overview
Stretching vibrations are vibrational motions that occur along the bond line, changing the bond length or distance between two bonded atoms. They are further distinguished as symmetric or asymmetric. In symmetric stretching, the...
Infrared (IR) Spectroscopy: Overview
Different compounds display unique properties due to their...
IR Spectroscopy: Hooke's Law Approximation of Molecular Vibration
According to Hooke's law, the vibrational frequency is directly proportional to the...
IR Spectrum Peak Intensity: Amount of IR-Active Bonds
IR Spectrometers
IR Spectrum Peak Intensity: Dipole Moment

