{ "id": "epa9z951pq", "slug": "vibrational-spectroscopy", "title": "Vibrational spectroscopy", "updated": "2026-10-15", "topic_path": [ { "id": "physical", "label": "Physical world and mathematics", "api_url": "https://www.edgepedia.org/api/v1/topics/physical" }, { "id": "physical.chemistry", "label": "Chemistry", "api_url": "https://www.edgepedia.org/api/v1/topics/physical.chemistry" }, { "id": "physical.chemistry.methods", "label": "Chemical principles and methods", "api_url": "https://www.edgepedia.org/api/v1/topics/physical.chemistry.methods" }, { "id": "physical.chemistry.methods.analytical-chemistry", "label": "Analytical chemistry", "api_url": "https://www.edgepedia.org/api/v1/topics/physical.chemistry.methods.analytical-chemistry" }, { "id": "physical.chemistry.methods.analytical-chemistry.vibrational-and-raman-spectroscopy", "label": "Vibrational and Raman spectroscopy", "api_url": "https://www.edgepedia.org/api/v1/topics/physical.chemistry.methods.analytical-chemistry.vibrational-and-raman-spectroscopy" } ], "geo": [ { "id": "geo.nongeo.t1800.physical.chemistry.methods.analytical-chemistry", "label": "Non-geographic · 1800 to 1945: Analytical chemistry", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800.physical.chemistry.methods.analytical-chemistry", "path": [ { "id": "geo.nongeo", "label": "Non-geographic", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo" }, { "id": "geo.nongeo.t1800", "label": "Non-geographic · 1800 to 1945", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800" }, { "id": "geo.nongeo.t1800.physical", "label": "Physical world and mathematics", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800.physical" }, { "id": "geo.nongeo.t1800.physical.chemistry", "label": "Chemistry", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800.physical.chemistry" }, { "id": "geo.nongeo.t1800.physical.chemistry.methods", "label": "Chemical principles and methods", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800.physical.chemistry.methods" }, { "id": "geo.nongeo.t1800.physical.chemistry.methods.analytical-chemistry", "label": "Analytical chemistry", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800.physical.chemistry.methods.analytical-chemistry" } ] }, { "id": "geo.nongeo.t1946.physical.chemistry.methods.analytical-chemistry.vibrational-and-raman-spectroscopy", "label": "Non-geographic · 1946 to 2000: Vibrational and Raman spectroscopy", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.physical.chemistry.methods.analytical-chemistry.vibrational-and-raman-spectroscopy", "path": [ { "id": "geo.nongeo", "label": "Non-geographic", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo" }, { "id": "geo.nongeo.t1946", "label": "Non-geographic · 1946 to 2000", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946" }, { "id": "geo.nongeo.t1946.physical", "label": "Physical world and mathematics", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.physical" }, { "id": "geo.nongeo.t1946.physical.chemistry", "label": "Chemistry", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.physical.chemistry" }, { "id": "geo.nongeo.t1946.physical.chemistry.methods", "label": "Chemical principles and methods", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.physical.chemistry.methods" }, { "id": "geo.nongeo.t1946.physical.chemistry.methods.analytical-chemistry", "label": "Analytical chemistry", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.physical.chemistry.methods.analytical-chemistry" }, { "id": "geo.nongeo.t1946.physical.chemistry.methods.analytical-chemistry.vibrational-and-raman-spectroscopy", "label": "Vibrational and Raman spectroscopy", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.physical.chemistry.methods.analytical-chemistry.vibrational-and-raman-spectroscopy" } ] } ], "excerpt": "Vibrational spectroscopy is a family of analytical techniques, mainly infrared absorption and Raman scattering, that identifies molecules from the characteristic frequencies of their vibrating bonds.", "snippet": "Vibrational spectroscopy is a family of analytical techniques, mainly infrared absorption and Raman scattering, that identifies molecules from the characteristic frequencies of their vibrating bonds.", "node": "physical.chemistry.methods.analytical-chemistry.vibrational-and-raman-spectroscopy", "markdown": "# Vibrational spectroscopy\n\nVibrational spectroscopy is a family of analytical techniques, principally infrared (IR) absorption and [Raman scattering](https://www.edgepedia.org/raman-scattering), that measures the characteristic frequencies at which molecular bonds vibrate, producing a chemical fingerprint that identifies functional groups, bonding, and molecular structure. The two techniques are complementary: IR absorption detects vibrations that change a molecule's dipole moment, while Raman detects those that change its polarizability (how easily a molecule's electron cloud is distorted). Raman scattering is intrinsically weak, with typically only about 1 in \\( 10^{8} \\) incident photons scattered inelastically,[1](https://www.intechopen.com/chapters/67751) and spontaneous Raman cross-sections of roughly \\( 10^{-30} \\) to \\( 10^{-28} \\) cm² per molecule against about \\( 10^{-19} \\) to \\( 10^{-17} \\) cm² for IR absorption.[2](https://pmc.ncbi.nlm.nih.gov/articles/PMC12927031/)\n\n| Key fact | Value |\n|---|---|\n| Number of normal modes | 3N − 6 for a nonlinear molecule, 3N − 5 for a linear one (N atoms)[3](https://chem.libretexts.org/Courses/Sewanee%3A_The_University_of_the_South/Instrumental_Analysis_%28CHEM_311%29/06%3A_Spectroscopic_Methods/6.11%3A_An_Introduction_to_Infrared_Spectrometry/6.11.01%3A_Theory_of_Infrared_Absorption_Spectrometry) |\n| Activity criterion | IR-active if a dipole-moment component changes during the vibration; Raman-active if a polarizability-tensor component changes[4](https://iris.unito.it/retrieve/handle/2318/1743927/630170/Chapter%204.6_vibrational%20spectroscopy_final.pdf) |\n| Mutual exclusion | In centrosymmetric molecules, IR-active modes are Raman-inactive and vice versa[5](https://alpha.chem.umb.edu/chemistry/ch370/CH370_Lectures/Lecture%20Documents/Ch04_10_Vibrations.pdf) |\n| FTIR spectral coverage | Far-IR 10–200 cm⁻¹, mid-IR 200–4000 cm⁻¹, near-IR 4000–12,000 cm⁻¹[6](https://www.ir.ethz.ch/handbook/MQ336_Handbook_Albert_KepplerAlbert_Quack%20bearbeitet.pdf) |\n| Raman signal strength | About 1 in \\( 10^{8} \\) incident photons Raman-scattered[1](https://www.intechopen.com/chapters/67751) |\n| SERS enhancement | Roughly \\( 10^{5} \\)–\\( 10^{11} \\)-fold at plasmonic hot spots[2](https://pmc.ncbi.nlm.nih.gov/articles/PMC12927031/) |\n| ATR probing depth | A few micrometers, set by incidence angle, wavelength, and refractive indices[4](https://iris.unito.it/retrieve/handle/2318/1743927/630170/Chapter%204.6_vibrational%20spectroscopy_final.pdf) |\n\n## How it works\n\nA molecular vibration is treated as a quantum harmonic oscillator, where \\( k \\) is the bond force constant and \\( \\mu \\) the reduced mass \\( m_{1} \\cdot m_{2}/(m_{1}+m_{2}) \\).[3](https://chem.libretexts.org/Courses/Sewanee%3A_The_University_of_the_South/Instrumental_Analysis_%28CHEM_311%29/06%3A_Spectroscopic_Methods/6.11%3A_An_Introduction_to_Infrared_Spectrometry/6.11.01%3A_Theory_of_Infrared_Absorption_Spectrometry) The harmonic selection rule allows transitions between adjacent vibrational levels, so an ideal oscillator gives one band per mode.[7](https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Quantum_Chemistry_with_Applications_in_Spectroscopy_%28Fleming%29/04%3A_The_Harmonic_Oscillator_and_Vibrational_Spectroscopy/4.04%3A_Vibrational_Spectroscopy_Techniques) Because real bonds are anharmonic, overtones with \\( \\Delta v = +2, +3 \\) appear weakly alongside fundamentals.[8](https://weichman.princeton.edu/wp-content/uploads/2024/10/chm305_2024_lecture12.pdf)\n\nThe two techniques probe the same energies by different routes. IR spectra arise from one-photon absorption with \\( h\\nu_{\\mathrm{abs}} = E_{2} - E_{1} \\); Raman spectra arise from inelastic two-photon scattering with \\( h\\nu_{\\mathrm{R}} = h\\nu_{0} \\pm (E_{2} - E_{1}) \\), the Stokes and anti-Stokes shifts.[9](https://old.vscht.cz/anl/vibspec/molecule-01eng.pdf) IR band intensities scale with the change in dipole moment, Raman intensities with the change in polarizability.[9](https://old.vscht.cz/anl/vibspec/molecule-01eng.pdf) The measured frequency yields bond stiffness: CO absorbs at 2143 cm⁻¹, from which a force constant of 1856 N/m is calculated (literature value 1860).[7](https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Quantum_Chemistry_with_Applications_in_Spectroscopy_%28Fleming%29/04%3A_The_Harmonic_Oscillator_and_Vibrational_Spectroscopy/4.04%3A_Vibrational_Spectroscopy_Techniques)\n\n[Group theory](https://www.edgepedia.org/group-theory) makes activity predictable. A normal mode is IR-active if it belongs to the same symmetry species as x, y, or z, and Raman-active if it belongs to the species of a binary direct product of vectors ( \\( x^{2} \\), \\( x \\cdot y \\), and so on).[5](https://alpha.chem.umb.edu/chemistry/ch370/CH370_Lectures/Lecture%20Documents/Ch04_10_Vibrations.pdf) For a tetrahedral XY₄ molecule only the two \\( T_{2} \\) modes are IR-active, but the \\( A_{1} \\), E, and \\( T_{2} \\) modes are all Raman-active, so Raman observes all four fundamentals.[5](https://alpha.chem.umb.edu/chemistry/ch370/CH370_Lectures/Lecture%20Documents/Ch04_10_Vibrations.pdf) In centrosymmetric molecules the rule of mutual exclusion applies, and some modes, such as \\( T_{2u} \\) in \\( SF_{6} \\), are silent in both spectra.[5](https://alpha.chem.umb.edu/chemistry/ch370/CH370_Lectures/Lecture%20Documents/Ch04_10_Vibrations.pdf) A Raman band with depolarization ratio \\( 0 < \\rho < 3/4 \\) is polarized and arises from a totally symmetric vibration; \\( \\rho = 3/4 \\) indicates a non-totally-symmetric mode.[5](https://alpha.chem.umb.edu/chemistry/ch370/CH370_Lectures/Lecture%20Documents/Ch04_10_Vibrations.pdf)\n\nPractical consequences follow. Homonuclear diatomics such as \\( H_{2} \\), \\( N_{2} \\), and \\( O_{2} \\) have no dipole change and therefore no IR spectrum, but they are Raman-active.[8](https://weichman.princeton.edu/wp-content/uploads/2024/10/chm305_2024_lecture12.pdf) Water is a strong IR absorber that complicates IR spectra, but its weak Raman cross-section makes Raman suitable for aqueous samples, which can even be measured through glass vessels; Raman also shows intense bands for symmetric bonds such as −C=C−, −N=N−, and −S−S−.[10](https://www.mdpi.com/1996-1073/8/4/3165)\n\n## How it is done\n\nAn FTIR spectrometer uses a Michelson-type interferometer; wavenumber calibration relies on the internal He-Ne laser at \\( \\lambda = 632.8 \\) nm (15,802.8 cm⁻¹), and the spectral resolution is approximately inversely proportional to the maximum optical path difference: if \\( \\Delta x \\) is the mirror travel, the optical path difference is about \\( 2\\Delta x \\), so the nominal resolution scales as \\( 1/(2\\Delta x) \\).[11](https://academics.nat.tum.de/fileadmin/w00bzl/nat/studium/org/gcnat/chapter_1_1_81.pdf) Components are chosen for the range: ceramic sources cover 9000–29 cm⁻¹ and mercury arcs 600–10 cm⁻¹; KBr beamsplitters cover 11,000–375 cm⁻¹ and Mylar 700–10 cm⁻¹; MCT detectors cover 12,000–450 cm⁻¹ and DLaTGS 18,000–150 cm⁻¹.[12](https://www.agilent.com/Library/posters/Public/K8000-90009.pdf)\n\nSampling matches the sample: gas cells of 1 cm to 10 m pathlength, liquid cells of 0.01–10 mm, and for solids KBr pellets or Nujol/Fluorolube mulls, plus accessories such as ATR, RAIRS, DRIFT, and [photoacoustic spectroscopy](https://www.edgepedia.org/photoacoustic-spectroscopy).[9](https://old.vscht.cz/anl/vibspec/molecule-01eng.pdf) ATR, the routine choice for liquids and solids, probes only a few micrometers.[4](https://iris.unito.it/retrieve/handle/2318/1743927/630170/Chapter%204.6_vibrational%20spectroscopy_final.pdf) Interpretation then proceeds by group frequencies: sp C–H at 3340–3280 cm⁻¹, alkene and aromatic C–H at 3100–3000 cm⁻¹, alkyl C–H below 3000 cm⁻¹.[9](https://old.vscht.cz/anl/vibspec/molecule-01eng.pdf)\n\nResolution is chosen against time. For condensed phases with mid-IR band widths of 10–12 cm⁻¹, about 4 cm⁻¹ suffices; doubling the resolution roughly doubles the noise, and an equivalent signal-to-noise spectrum at twice the resolution takes eight times longer including background.[13](https://theanalyticalscientist.com/media/fsln4doy/an_m71_spectral_resolution_en.pdf) FTIR probing depth ranges from 100 Å to 1 mm depending on transparency, and quantification with standards reaches 5–10% accuracy.[14](https://glass.rutgers.edu/sites/default/files/uploads/virtual/dir.cullity/B-ch.8.1%2C8.2-IR-Raman.pdf) Because the Raman cross-section scales as \\( \\lambda^{-4} \\), shorter-wavelength lasers give stronger signal at equal power.[10](https://www.mdpi.com/1996-1073/8/4/3165)\n\n## Origin\n\nThe Raman effect was put on firmer ground by Kramers and Heisenberg's dispersion theory.[15](https://link.springer.com/chapter/10.1007/978-3-032-09188-8_6) [C. V. Raman](https://www.edgepedia.org/c-v-raman) and K. S. Krishnan reported the modified secondary radiation in Nature in 1928,[16](https://doi.org/10.1038/121501c0) and used it to deduce hitherto unknown infrared lines of carbon tetrachloride at 45.4, 31.8, and 21.7 μ from frequency shifts of scattered mercury-arc lines.[17](https://www.nature.com/articles/122278a0) Raman alone received the 1930 Nobel Prize in physics.[18](https://iopscience.iop.org/article/10.1070/PU1998v041n12ABEH000516)\n\n[Gerhard Herzberg](https://www.edgepedia.org/gerhard-herzberg)'s 1945 volume Infrared and Raman Spectra of Polyatomic Molecules marks the start of the modern era.[19](https://pubs.rsc.org/en/content/articlehtml/2013/an/c3an90035e) The first laser-based Raman experiment followed in 1962,[20](https://pubs.rsc.org/en/content/articlehtml/2025/cs/d4cs00883a) and the 1965 double monochromator for stray-light discrimination made the modern Raman spectrometer possible.[14](https://glass.rutgers.edu/sites/default/files/uploads/virtual/dir.cullity/B-ch.8.1%2C8.2-IR-Raman.pdf) On the IR side, interferometric spectroscopy goes back to Michelson's 1881 interferometer, with key contributions by Jacquinot (1954), Fellgett (1958), and Connes (1961); the first commercial FTIR spectrometer appeared in 1969 and the first FTIR microscope in 1982.[12](https://www.agilent.com/Library/posters/Public/K8000-90009.pdf)\n\nFor Raman specifically, G. W. Chantry, H. A. Gebbie, and C. Hilsum reported interferometric [Raman spectroscopy](https://www.edgepedia.org/raman-spectroscopy) using infrared excitation in Nature in 1964, the precursor of FT-Raman,[21](https://doi.org/10.1038/2031052a0) and T. Hirschfeld and B. Chase presented the development and justification of FT-Raman spectroscopy in Applied Spectroscopy in 1986.[22](https://doi.org/10.1366/0003702864509538)\n\n## Variants\n\n**SERS** originated in 1974, when M. Fleischmann, P. J. Hendra, and A. J. McQuillan reported potential-dependent Raman spectra of pyridine on a roughened silver electrode.[23](https://doi.org/10.1016/0009-2614%2874%2985388-1) Van Duyne and Jeanmaire measured a \\(10^{5}\\)–\\(10^{6}\\)-fold cross-section enhancement for adsorbed pyridine,[20](https://pubs.rsc.org/en/content/articlehtml/2025/cs/d4cs00883a) while later reviews attribute \\(10^{8}\\)–\\(10^{10}\\) to electromagnetic (surface plasmon) enhancement and \\(10^{2}\\)–\\(10^{3}\\) to chemical enhancement; the plasmon mechanism was put forward by [M. Moskovits](https://www.edgepedia.org/martin-moskovits), whose 1982 Journal of Chemical Physics paper established surface selection rules for SERS.[24](https://link.springer.com/article/10.1186/s11671-019-3039-2) Single-molecule SERS detection was reported by Katrin Kneipp and colleagues in [Physical Review Letters](https://www.edgepedia.org/physical-review-letters) in 1997.[25](https://doi.org/10.1103/physrevlett.78.1667) Commercial gold substrates work best with 785 nm excitation and silver with 532 nm, and silver substrates degrade within 2–3 weeks by oxidation.[26](https://www.oceanoptics.com/wp-content/uploads/2025/04/SERS_User-Manual.pdf)\n\n**TERS** combines Raman spectroscopy with apertureless near-field scanning microscopy using a plasmon-resonant metallic tip, achieving 1–10 nm resolution set by the tip apex; it was introduced by Raoul M. Stöckle and colleagues in Chemical Physics Letters in 2000.[27](https://doi.org/10.1016/s0009-2614%2899%2901451-7) Plasmon-enhanced chemical mapping of a single molecule at subnanometre resolution was reported by R. Zhang and colleagues in Nature in 2013.[28](https://doi.org/10.1038/nature12151) SHINERS extends SERS to atomically flat single crystals.[20](https://pubs.rsc.org/en/content/articlehtml/2025/cs/d4cs00883a) In resonance Raman, excitation is tuned to an electronic transition of a chromophore, selectively enhancing that group's modes.[29](https://content.e-bookshelf.de/media/reading/L-603421-76d630a87c.pdf) [Coherent anti-Stokes Raman spectroscopy](https://www.edgepedia.org/coherent-anti-stokes-raman-spectroscopy) (CARS), reported by R. F. Begley, A. B. Harvey, and R. L. Byer in [Applied Physics Letters](https://www.edgepedia.org/applied-physics-letters) in 1974, offers a \\( 10^{5} \\) increase in conversion efficiency and discrimination against fluorescence without a monochromator.[30](https://doi.org/10.1063/1.1655519) [Stimulated Raman scattering](https://www.edgepedia.org/stimulated-raman-scattering) (SRS) microscopy enables rapid imaging of single Raman bands in biological specimens.[31](https://www.frontiersin.org/journals/chemical-biology/articles/10.3389/fchbi.2026.1754307/full) On the IR side, nano-FTIR absorption spectroscopy of molecular fingerprints at 20 nm spatial resolution was reported by Florian Huth and colleagues in Nano Letters in 2012.[32](https://doi.org/10.1021/nl301159v)\n\n## Applications\n\nSERS applications have expanded from surface chemistry to material characterization, bioanalysis, drug analysis, food safety, and environmental monitoring.[20](https://pubs.rsc.org/en/content/articlehtml/2025/cs/d4cs00883a) In biomedicine, handheld Raman devices with machine-learning classification have been used for rapid intraoperative tissue assessment.[33](https://www.mdpi.com/1424-8220/26/1/341) For proteins, FTIR and Raman quantify secondary-structure contributions and, with a time window beyond \\( 10^{-12} \\,\\mathrm{s} \\), suit studies of folding and unfolding dynamics.[34](https://www.sciencedirect.com/science/article/abs/pii/S0924203106000063)\n\n## Limitations and alternatives\n\nThe dominant Raman failure mode is fluorescence: because fluorescence cross-sections greatly exceed Raman cross-sections, Raman peaks ride on a broad background, and aromatic compounds excited in the visible or UV are especially prone to emit. Remedies include near-IR or deep-UV excitation, polarization-resolved detection, SERDS, and multivariate signal processing.[1](https://www.intechopen.com/chapters/67751) Rayleigh and [Mie scattering](https://www.edgepedia.org/mie-scattering) from particles can exceed the Raman signal by orders of magnitude and requires notch or long-pass filters.[10](https://www.mdpi.com/1996-1073/8/4/3165) Sample heating is a real risk: laser power in Raman typically runs from a few µW to several hundred mW, and a few mW focused on nanostructures can reach the melting point.[4](https://iris.unito.it/retrieve/handle/2318/1743927/630170/Chapter%204.6_vibrational%20spectroscopy_final.pdf) In IR, water's strong absorption complicates spectra of aqueous or wet samples.[10](https://www.mdpi.com/1996-1073/8/4/3165) TERS tips, especially silver ones, have short lifetimes and suffer mechanical damage, laser heating, and contamination.[35](https://pubs.acs.org/doi/full/10.1021/acs.analchem.6b02093) One review of SERS and TERS states that despite the vast number of proposed applications, \"none has been applied to real practical use,\" a verdict other literature on commercial SERS substrates does not support.[36](https://pmc.ncbi.nlm.nih.gov/articles/PMC9952515/)\n\nFor structure determination, vibrational spectroscopy is generally considered a low-resolution technique compared with NMR and [X-ray crystallography](https://www.edgepedia.org/x-ray-crystallography): [X-ray diffraction](https://www.edgepedia.org/x-ray-diffraction) reaches atomic resolution but gives a static picture and requires successful crystallization, while NMR relaxation-dispersion experiments such as CPMG probe conformational exchange on the microsecond-to-millisecond timescale, and other NMR methods access faster or slower motions. [Mass spectrometry](https://www.edgepedia.org/mass-spectrometry) provides molecular masses from trace quantities but is destructive for solids, and conventional solution NMR often uses about 0.5 mL in a standard 5 mm tube, though sample requirements vary, with low sensitivity for direct solid measurements.[34](https://www.sciencedirect.com/science/article/abs/pii/S0924203106000063) Recent advances such as vibrational optical activity, isotopic labeling, and 2D-IR allow discrimination of α- versus 3₁₀-helices but do not make vibrational spectroscopy competitive with NMR for full structure solution.[34](https://www.sciencedirect.com/science/article/abs/pii/S0924203106000063)\n\n## References\n\n1. [What Is Vibrational Raman Spectroscopy: A Vibrational or an Electronic Spectroscopic Technique or Both? (IntechOpen)](https://www.intechopen.com/chapters/67751)\n2. [Far-field single-molecule vibrational spectroscopy and imaging (PMC Perspective)](https://pmc.ncbi.nlm.nih.gov/articles/PMC12927031/)\n3. [6.11.01: Theory of Infrared Absorption Spectrometry (chem.libretexts.org)](https://chem.libretexts.org/Courses/Sewanee%3A_The_University_of_the_South/Instrumental_Analysis_%28CHEM_311%29/06%3A_Spectroscopic_Methods/6.11%3A_An_Introduction_to_Infrared_Spectrometry/6.11.01%3A_Theory_of_Infrared_Absorption_Spectrometry)\n4. [Chapter 4.6 Vibrational spectroscopy (AperTO, Università di Torino)](https://iris.unito.it/retrieve/handle/2318/1743927/630170/Chapter%204.6_vibrational%20spectroscopy_final.pdf)\n5. [Spectroscopic Selection Rules (CH370 lecture, UMass Boston)](https://alpha.chem.umb.edu/chemistry/ch370/CH370_Lectures/Lecture%20Documents/Ch04_10_Vibrations.pdf)\n6. [High-resolution Fourier Transform Infrared Spectroscopy (Handbook of High-resolution Spectroscopy, Albert & Quack)](https://www.ir.ethz.ch/handbook/MQ336_Handbook_Albert_KepplerAlbert_Quack%20bearbeitet.pdf)\n7. [4.04: Vibrational Spectroscopy Techniques (chem.libretexts.org)](https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Quantum_Chemistry_with_Applications_in_Spectroscopy_%28Fleming%29/04%3A_The_Harmonic_Oscillator_and_Vibrational_Spectroscopy/4.04%3A_Vibrational_Spectroscopy_Techniques)\n8. [CHM 305 Lecture 12: Molecular Spectroscopy (Princeton)](https://weichman.princeton.edu/wp-content/uploads/2024/10/chm305_2024_lecture12.pdf)\n9. [Techniques of measurement and interpretation of IR and Raman spectra (UCT Prague slides)](https://old.vscht.cz/anl/vibspec/molecule-01eng.pdf)\n10. [Recent Advances in the Characterization of Gaseous and Liquid Fuels by Vibrational Spectroscopy (Energies, MDPI)](https://www.mdpi.com/1996-1073/8/4/3165)\n11. [Practical IR and Raman Spectroscopy (TUM course)](https://academics.nat.tum.de/fileadmin/w00bzl/nat/studium/org/gcnat/chapter_1_1_81.pdf)\n12. [Agilent FTIR Spectroscopy Reference Guide poster](https://www.agilent.com/Library/posters/Public/K8000-90009.pdf)\n13. [Bruker Application Note AN M71: Spectral Resolution in FTIR Spectrometry](https://theanalyticalscientist.com/media/fsln4doy/an_m71_spectral_resolution_en.pdf)\n14. [Encyclopedia of Materials Characterization, ch. 8: Vibrational Spectroscopies (IR and Raman)](https://glass.rutgers.edu/sites/default/files/uploads/virtual/dir.cullity/B-ch.8.1%2C8.2-IR-Raman.pdf)\n15. [The Raman Effect: How Virtual Transitions Became 'Virtual' (Springer chapter)](https://link.springer.com/chapter/10.1007/978-3-032-09188-8_6)\n16. [C. V. RAMAN, K. S. KRISHNAN (1928). A New Type of Secondary Radiation. Nature.](https://doi.org/10.1038/121501c0)\n17. [Molecular Spectra in the Extreme Infra-Red (C. V. Raman & K. S. Krishnan, Nature 122, 278, 1928)](https://www.nature.com/articles/122278a0)\n18. [Seventy years of combination (Raman) scattering (I. L. Fabelinskiĭ, Physics-Uspekhi 41, 1229, 1998)](https://iopscience.iop.org/article/10.1070/PU1998v041n12ABEH000516)\n19. [The road to medical vibrational spectroscopy – a history (The Analyst, 2013)](https://pubs.rsc.org/en/content/articlehtml/2013/an/c3an90035e)\n20. [Surface-enhanced Raman spectroscopy: a half-century historical perspective (Chemical Society Reviews, 2025)](https://pubs.rsc.org/en/content/articlehtml/2025/cs/d4cs00883a)\n21. [G. W. CHANTRY, H. A. GEBBIE, C. HILSUM (1964). Interferometric Raman Spectroscopy Using Infra-Red Excitation. Nature.](https://doi.org/10.1038/2031052a0)\n22. [T. Hirschfeld, B. Chase (1986). FT-Raman Spectroscopy: Development and Justification. Applied Spectroscopy.](https://doi.org/10.1366/0003702864509538)\n23. 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[Toward a New Era of SERS and TERS at the Nanometer Scale: From Fundamentals to Innovative Applications (PMC review)](https://pmc.ncbi.nlm.nih.gov/articles/PMC9952515/)\n\n---\n*Topic: Encyclopedia › Physical world and mathematics › Chemistry › Chemical principles and methods › Analytical chemistry › Vibrational and Raman spectroscopy*\n\n*Initially written Sep 29, 2026 · Edited: Oct 15, 2026*\n\n*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*\n\nLicense: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license\n", "same_as": [], "url": "https://www.edgepedia.org/vibrational-spectroscopy", "markdown_url": "https://www.edgepedia.org/vibrational-spectroscopy.md", "license": { "name": "Edgepedia Community License 1.0", "url": "https://www.edgepedia.org/edgepedia/license", "summary": "Free with credit, commercial use included. AI training is open to everyone. For other uses, organizations over USD 100M in revenue or 100M monthly users license separately.", "spdx": "LicenseRef-Edgepedia-Community-1.0" }, "credit": "\"Vibrational spectroscopy\", Edgepedia (EdgeChat), https://www.edgepedia.org/vibrational-spectroscopy. Edgepedia Community License 1.0.", "credit_md": "\"[Vibrational spectroscopy](https://www.edgepedia.org/vibrational-spectroscopy)\", Edgepedia (EdgeChat), [https://www.edgepedia.org/vibrational-spectroscopy](https://www.edgepedia.org/vibrational-spectroscopy). [Edgepedia Community License 1.0](https://www.edgepedia.org/edgepedia/license).", "credit_html": "\"Vibrational spectroscopy\", Edgepedia (EdgeChat), https://www.edgepedia.org/vibrational-spectroscopy. Edgepedia Community License 1.0.", "speakable": "Vibrational spectroscopy is a family of analytical techniques, mainly infrared absorption and Raman scattering, that identifies molecules from the characteristic frequencies of their vibrating bonds." }