By SpectralBench Editorial Team3 min read
Raman Peak Identification Table — Common Raman Shifts & Band Assignments
This searchable Raman peak identification table covers over 80 common Raman spectroscopy peaks organized by material class — organic functional groups, aromatic compounds, polymers, carbon materials, minerals, biological molecules, solvents, and gases. Search by assignment name, material, or wavenumber to instantly filter results. Click any row to see detailed notes and a visual position bar.
The same data powers SpectralBench's Raman Peak Identifier — the automated tool that detects peaks in your uploaded Raman spectrum and matches them against known assignments.
| Material / Bond | Raman Shift (cm⁻¹) | Relative Intensity | Assignment |
|---|---|---|---|
| Anatase (TiO₂) | 144 | Strong | Eg mode — distinguishes anatase from rutile |
| Quartz (SiO₂) | 464 | Strong | Si-O-Si bending — common mineral marker |
| S-S disulfide | 500–550 | Strong | Disulfide stretch — proteins, rubber (IR-inactive) |
| Crystalline silicon | 520 | Strong | First-order optical phonon — calibration standard |
| Tryptophan | 759 | Strong | Indole ring breathing — protein marker |
| Polypropylene | 809 | Strong | CH₃ rocking — polymer identification |
| Hydroxyapatite (bone) | 960 | Strong | Symmetric PO₄³⁻ stretch — bone mineral marker |
| Sulfate (SO₄²⁻) | 983 | Strong | Symmetric stretch — free sulfate ion |
| Polystyrene / benzene ring | 1001 | Strong | Ring breathing — calibration standard |
| Calcite (CaCO₃) | 1086 | Strong | Symmetric CO₃²⁻ stretch — carbonate minerals |
| D band (carbon) | 1350 | Variable | Disorder/defect band — carbon crystallinity |
| Carotenoid | 1525 | Strong | C=C stretch — resonance-enhanced biological pigment |
| G band (graphitic carbon) | 1580 | Strong | E₂g mode of sp² carbon — graphene, nanotubes |
| C=C aromatic ring | 1600 | Strong | Aromatic quadrant stretch — universal aromatic marker |
| Amide I (protein) | 1655 | Medium | C=O stretch — protein secondary structure |
| C≡N nitrile | 2200–2260 | Strong | Triple-bond stretch — diagnostic silent-region peak |
| C-H aliphatic | 2850–2960 | Strong | CH₂/CH₃ symmetric and asymmetric stretch |
| C-H aromatic | 3000–3100 | Medium | sp² C-H stretch — above 3000 cm⁻¹ distinguishes from sp³ |
How to use this table
- Find your peak position (Raman shift in cm⁻¹) from your spectrum.
- Type the wavenumber into the search box to highlight matching entries, or browse by material class.
- Use the intensity (strong, medium, weak) and context notes to narrow your assignment — a strong Raman peak from a symmetric vibration is more likely than a weak one.
- Confirm your assignment by checking for additional corroborating peaks from the same material listed in the description.
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Organic Functional Groups
| Assignment | Range (cm⁻¹) | Intensity | Notes | |
|---|---|---|---|---|
O-H stretch | 3200–3600 | weak | Weak in Raman (strong in IR). Broad band from hydrogen bonding. Water shows a … | |
N-H stretch | 3300–3500 | weak | Weak Raman scatterer. Primary amines show two bands; secondary amines show one. | |
C-H stretch (aromatic/sp²) | 3000–3100 | medium | Aromatic and olefinic C-H stretching. Appears above 3000 cm⁻¹, distinguishing … | |
C-H stretch (aliphatic/sp³) | 2800–3000 | strong | CH₃ symmetric stretch near 2870 cm⁻¹, CH₂ symmetric near 2850 cm⁻¹, antisymmet… | |
S-H stretch | 2550–2600 | strong | Strong Raman, weak IR. Diagnostic for thiols. Sharp peak, useful for detecting… | |
C≡N stretch (nitrile) | 2200–2260 | strong | Strong, sharp Raman band. Appears in the silent region where few other peaks o… | |
C≡C stretch (alkyne) | 2100–2260 | strong | Strong Raman scatterer, especially for symmetrical alkynes that are IR-inactiv… | |
C=O stretch (carbonyl) | 1650–1780 | medium | Moderate in Raman (very strong in IR). Ketones ~1715 cm⁻¹, esters ~1735 cm⁻¹, … | |
C=C stretch (alkene) | 1620–1680 | strong | Strong Raman, often weak IR. Isolated alkenes near 1640 cm⁻¹; conjugation lowe… | |
C=C aromatic ring stretch | 1580–1620 | strong | Strong Raman band near 1600 cm⁻¹. One of the most reliable aromatic markers in… | |
NO₂ asymmetric stretch | 1500–1570 | medium | Moderate Raman intensity. Aromatic nitro compounds show this along with the sy… | |
CH₂ / CH₃ deformation | 1430–1470 | medium | CH₂ scissoring near 1450 cm⁻¹, CH₃ asymmetric deformation near 1460 cm⁻¹. Pres… | |
NO₂ symmetric stretch | 1320–1360 | strong | Strong Raman scatterer. Symmetric stretches are characteristically stronger in… | |
C-O stretch (ester/ether) | 1000–1300 | medium | Moderate Raman. Esters show C-O near 1250 cm⁻¹; ethers near 1100 cm⁻¹. Overlap… | |
S-S disulfide stretch | 500–550 | strong | Extremely strong in Raman, nearly invisible in IR. Diagnostic for protein disu… | |
C-S stretch | 630–720 | strong | Strong, polarizable bond. Diagnostic for thioethers and organosulfur compounds. | |
C-C skeletal stretch | 800–1100 | medium | Backbone vibrations of alkyl chains. Position depends on chain conformation (g… |
O-H stretch
3200–3600 cm⁻¹
weak
Weak in Raman (strong in IR). Broad band from hydrogen bonding. Water shows a broad feature near 3…
N-H stretch
3300–3500 cm⁻¹
weak
Weak Raman scatterer. Primary amines show two bands; secondary amines show one.
C-H stretch (aromatic/sp²)
3000–3100 cm⁻¹
medium
Aromatic and olefinic C-H stretching. Appears above 3000 cm⁻¹, distinguishing sp² from sp³ C-H.
C-H stretch (aliphatic/sp³)
2800–3000 cm⁻¹
strong
CH₃ symmetric stretch near 2870 cm⁻¹, CH₂ symmetric near 2850 cm⁻¹, antisymmetric stretches near 2…
S-H stretch
2550–2600 cm⁻¹
strong
Strong Raman, weak IR. Diagnostic for thiols. Sharp peak, useful for detecting cysteine in proteins.
C≡N stretch (nitrile)
2200–2260 cm⁻¹
strong
Strong, sharp Raman band. Appears in the silent region where few other peaks occur. Highly diagnos…
C≡C stretch (alkyne)
2100–2260 cm⁻¹
strong
Strong Raman scatterer, especially for symmetrical alkynes that are IR-inactive. Silent region mar…
C=O stretch (carbonyl)
1650–1780 cm⁻¹
medium
Moderate in Raman (very strong in IR). Ketones ~1715 cm⁻¹, esters ~1735 cm⁻¹, amides (amide I) ~16…
C=C stretch (alkene)
1620–1680 cm⁻¹
strong
Strong Raman, often weak IR. Isolated alkenes near 1640 cm⁻¹; conjugation lowers frequency.
C=C aromatic ring stretch
1580–1620 cm⁻¹
strong
Strong Raman band near 1600 cm⁻¹. One of the most reliable aromatic markers in Raman spectroscopy.
NO₂ asymmetric stretch
1500–1570 cm⁻¹
medium
Moderate Raman intensity. Aromatic nitro compounds show this along with the symmetric stretch.
CH₂ / CH₃ deformation
1430–1470 cm⁻¹
medium
CH₂ scissoring near 1450 cm⁻¹, CH₃ asymmetric deformation near 1460 cm⁻¹. Present in most organic …
NO₂ symmetric stretch
1320–1360 cm⁻¹
strong
Strong Raman scatterer. Symmetric stretches are characteristically stronger in Raman than IR.
C-O stretch (ester/ether)
1000–1300 cm⁻¹
medium
Moderate Raman. Esters show C-O near 1250 cm⁻¹; ethers near 1100 cm⁻¹. Overlap with fingerprint re…
S-S disulfide stretch
500–550 cm⁻¹
strong
Extremely strong in Raman, nearly invisible in IR. Diagnostic for protein disulfide bridges and vu…
C-S stretch
630–720 cm⁻¹
strong
Strong, polarizable bond. Diagnostic for thioethers and organosulfur compounds.
C-C skeletal stretch
800–1100 cm⁻¹
medium
Backbone vibrations of alkyl chains. Position depends on chain conformation (gauche vs trans).
Aromatic Compounds
| Assignment | Range (cm⁻¹) | Intensity | Notes | |
|---|---|---|---|---|
Ring breathing (monosubstituted) | 990–1010 | strong | Very strong, sharp peak near 1000 cm⁻¹. The classic Raman marker for monosubst… | |
Ring breathing (para-disubstituted) | 630–650 | strong | Strong ring breathing mode shifted to lower frequency by para substitution. | |
Aromatic ring stretch (~1600) | 1585–1610 | strong | Quadrant stretching mode. Very strong in Raman. Appears as a doublet with the … | |
Aromatic ring stretch (~1500) | 1480–1510 | medium | Semicircle stretching mode. Medium Raman intensity. Useful for confirming arom… | |
Aromatic C-H in-plane bend | 1000–1300 | weak | Weak to medium Raman bands. Multiple bands in this region; pattern depends on … | |
Aromatic C-H out-of-plane bend | 700–900 | weak | Weak in Raman (strong in IR). Position depends on substitution pattern: mono ~… |
Ring breathing (monosubstituted)
990–1010 cm⁻¹
strong
Very strong, sharp peak near 1000 cm⁻¹. The classic Raman marker for monosubstituted benzene rings…
Ring breathing (para-disubstituted)
630–650 cm⁻¹
strong
Strong ring breathing mode shifted to lower frequency by para substitution.
Aromatic ring stretch (~1600)
1585–1610 cm⁻¹
strong
Quadrant stretching mode. Very strong in Raman. Appears as a doublet with the ~1580 cm⁻¹ band in s…
Aromatic ring stretch (~1500)
1480–1510 cm⁻¹
medium
Semicircle stretching mode. Medium Raman intensity. Useful for confirming aromatic character along…
Aromatic C-H in-plane bend
1000–1300 cm⁻¹
weak
Weak to medium Raman bands. Multiple bands in this region; pattern depends on substitution.
Aromatic C-H out-of-plane bend
700–900 cm⁻¹
weak
Weak in Raman (strong in IR). Position depends on substitution pattern: mono ~750 cm⁻¹, para ~800 …
Polymers
| Assignment | Range (cm⁻¹) | Intensity | Notes | |
|---|---|---|---|---|
Polystyrene (ring breathing) | 999–1003 | strong | Sharp peak at 1001 cm⁻¹. One of the most recognized Raman peaks; polystyrene i… | |
Polyethylene (C-C stretch) | 1060–1130 | strong | Peaks at 1062 and 1130 cm⁻¹ from C-C stretching. CH₂ twist at 1295 cm⁻¹ and C-… | |
Polypropylene (CH₃ rock) | 807–812 | strong | Characteristic peak near 809 cm⁻¹ from CH₃ rocking. Additional peaks at 841, 9… | |
PET (ring C=C stretch) | 1610–1620 | strong | Aromatic ring stretch near 1614 cm⁻¹. C=O at 1726 cm⁻¹, ring breathing at 858 … | |
PMMA (C=O / C-O-C stretch) | 810–815 | strong | Peak near 812 cm⁻¹ from C-O-C stretch. C=O at 1728 cm⁻¹, C-C-O at 600 cm⁻¹, CH… | |
Nylon / Polyamide (amide I) | 1630–1640 | medium | Amide I (C=O) near 1634 cm⁻¹. Amide III near 1280 cm⁻¹, N-H stretch near 3300 … | |
PVC (C-Cl stretch) | 630–700 | strong | C-Cl stretching near 636 and 694 cm⁻¹. Strong, polarizable bond makes this a r… | |
PTFE / Teflon (C-F stretch) | 730–740 | strong | Symmetric CF₂ stretching near 734 cm⁻¹. PTFE also shows bands at 1215, 1301, a… | |
Polycarbonate (carbonate stretch) | 885–890 | strong | O-C-O stretch near 888 cm⁻¹. Ring breathing near 1005 cm⁻¹, C=O near 1775 cm⁻¹… |
Polystyrene (ring breathing)
999–1003 cm⁻¹
strong
Sharp peak at 1001 cm⁻¹. One of the most recognized Raman peaks; polystyrene is used as a Raman ca…
Polyethylene (C-C stretch)
1060–1130 cm⁻¹
strong
Peaks at 1062 and 1130 cm⁻¹ from C-C stretching. CH₂ twist at 1295 cm⁻¹ and C-H stretches near 285…
Polypropylene (CH₃ rock)
807–812 cm⁻¹
strong
Characteristic peak near 809 cm⁻¹ from CH₃ rocking. Additional peaks at 841, 972, 1152, 1330, 1460…
PET (ring C=C stretch)
1610–1620 cm⁻¹
strong
Aromatic ring stretch near 1614 cm⁻¹. C=O at 1726 cm⁻¹, ring breathing at 858 cm⁻¹, C-H near 3080 …
PMMA (C=O / C-O-C stretch)
810–815 cm⁻¹
strong
Peak near 812 cm⁻¹ from C-O-C stretch. C=O at 1728 cm⁻¹, C-C-O at 600 cm⁻¹, CH₃ at 2950 cm⁻¹.
Nylon / Polyamide (amide I)
1630–1640 cm⁻¹
medium
Amide I (C=O) near 1634 cm⁻¹. Amide III near 1280 cm⁻¹, N-H stretch near 3300 cm⁻¹, C-H stretch ne…
PVC (C-Cl stretch)
630–700 cm⁻¹
strong
C-Cl stretching near 636 and 694 cm⁻¹. Strong, polarizable bond makes this a reliable PVC marker.
PTFE / Teflon (C-F stretch)
730–740 cm⁻¹
strong
Symmetric CF₂ stretching near 734 cm⁻¹. PTFE also shows bands at 1215, 1301, and 1380 cm⁻¹.
Polycarbonate (carbonate stretch)
885–890 cm⁻¹
strong
O-C-O stretch near 888 cm⁻¹. Ring breathing near 1005 cm⁻¹, C=O near 1775 cm⁻¹. Common in eyewear …
Carbon Materials
| Assignment | Range (cm⁻¹) | Intensity | Notes | |
|---|---|---|---|---|
D band (disordered carbon) | 1330–1370 | variable | Disorder-activated breathing mode. Absent in pristine graphene, strong in amor… | |
G band (graphitic carbon) | 1570–1600 | strong | E₂g phonon mode of sp² carbon. Present in graphite, graphene, carbon nanotubes… | |
2D band (graphene/graphite) | 2650–2700 | strong | Second-order overtone of D band. Sharp single peak in monolayer graphene; spli… | |
Diamond (sp³ carbon) | 1330–1334 | strong | Sharp peak at 1332 cm⁻¹ from the triply degenerate T₂g mode. The strongest fir… | |
Carbon nanotube RBM | 100–350 | strong | Radial breathing mode (RBM). Frequency inversely proportional to tube diameter… | |
Amorphous carbon (broad D+G) | 1300–1600 | strong | Broad, overlapping D and G bands. Peak positions and widths indicate sp²/sp³ r… |
D band (disordered carbon)
1330–1370 cm⁻¹
variable
Disorder-activated breathing mode. Absent in pristine graphene, strong in amorphous carbon. I(D)/I…
G band (graphitic carbon)
1570–1600 cm⁻¹
strong
E₂g phonon mode of sp² carbon. Present in graphite, graphene, carbon nanotubes, and carbon fibers.…
2D band (graphene/graphite)
2650–2700 cm⁻¹
strong
Second-order overtone of D band. Sharp single peak in monolayer graphene; splits in bilayer/graphi…
Diamond (sp³ carbon)
1330–1334 cm⁻¹
strong
Sharp peak at 1332 cm⁻¹ from the triply degenerate T₂g mode. The strongest first-order Raman peak …
Carbon nanotube RBM
100–350 cm⁻¹
strong
Radial breathing mode (RBM). Frequency inversely proportional to tube diameter: ω ≈ 234/d + 10 (cm…
Amorphous carbon (broad D+G)
1300–1600 cm⁻¹
strong
Broad, overlapping D and G bands. Peak positions and widths indicate sp²/sp³ ratio and degree of d…
Minerals & Inorganics
| Assignment | Range (cm⁻¹) | Intensity | Notes | |
|---|---|---|---|---|
Quartz (SiO₂) | 462–467 | strong | Sharp peak at 464 cm⁻¹ from Si-O-Si bending. Additional peaks at 128, 206, 356… | |
Calcite (CaCO₃) | 1083–1090 | strong | Symmetric CO₃²⁻ stretch at 1086 cm⁻¹. Lattice modes at 155 and 282 cm⁻¹. Easil… | |
Aragonite (CaCO₃) | 1083–1088 | strong | Symmetric stretch near 1085 cm⁻¹ (similar to calcite). Distinguished by lattic… | |
Gypsum (CaSO₄·2H₂O) | 1006–1010 | strong | Symmetric SO₄²⁻ stretch at 1008 cm⁻¹. Very sharp and intense. Additional peaks… | |
Sulfate (SO₄²⁻) symmetric stretch | 980–1010 | strong | Strong, sharp peak. Position varies with cation: free sulfate ~983 cm⁻¹, barit… | |
Phosphate (PO₄³⁻) symmetric stretch | 940–970 | strong | Strong Raman band. Apatite at 964 cm⁻¹ — the primary bone mineral marker. Free… | |
Anatase (TiO₂) | 141–147 | strong | Very strong Eg mode at 144 cm⁻¹. Additional modes at 197, 399, 513, and 639 cm… | |
Rutile (TiO₂) | 440–450 | strong | Eg mode at 447 cm⁻¹ and A₁g mode at 612 cm⁻¹. Distinguished from anatase by th… | |
Silicon (crystalline) | 518–522 | strong | Sharp peak at 520 cm⁻¹ from the first-order optical phonon. Used as a universa… | |
Hematite (Fe₂O₃) | 220–230 | strong | Strongest peak near 225 cm⁻¹ (A₁g mode). Additional modes at 245, 292, 410, 49… | |
Magnetite (Fe₃O₄) | 660–670 | strong | A₁g mode near 668 cm⁻¹. Additional peak at 538 cm⁻¹. Distinguishable from hema… | |
Feldspar (aluminosilicate) | 505–515 | strong | Strong peak near 510 cm⁻¹ from framework vibrations. Specific position varies … | |
Carbonate (CO₃²⁻) symmetric stretch | 1070–1090 | strong | Symmetric stretch of the carbonate ion. Very strong, sharp peak. Position vari… |
Quartz (SiO₂)
462–467 cm⁻¹
strong
Sharp peak at 464 cm⁻¹ from Si-O-Si bending. Additional peaks at 128, 206, 356, and 1085 cm⁻¹. Com…
Calcite (CaCO₃)
1083–1090 cm⁻¹
strong
Symmetric CO₃²⁻ stretch at 1086 cm⁻¹. Lattice modes at 155 and 282 cm⁻¹. Easily distinguished from…
Aragonite (CaCO₃)
1083–1088 cm⁻¹
strong
Symmetric stretch near 1085 cm⁻¹ (similar to calcite). Distinguished by lattice modes at 152, 181,…
Gypsum (CaSO₄·2H₂O)
1006–1010 cm⁻¹
strong
Symmetric SO₄²⁻ stretch at 1008 cm⁻¹. Very sharp and intense. Additional peaks at 414, 493, and 62…
Sulfate (SO₄²⁻) symmetric stretch
980–1010 cm⁻¹
strong
Strong, sharp peak. Position varies with cation: free sulfate ~983 cm⁻¹, barite 988 cm⁻¹, gypsum 1…
Phosphate (PO₄³⁻) symmetric stretch
940–970 cm⁻¹
strong
Strong Raman band. Apatite at 964 cm⁻¹ — the primary bone mineral marker. Free phosphate near 940 …
Anatase (TiO₂)
141–147 cm⁻¹
strong
Very strong Eg mode at 144 cm⁻¹. Additional modes at 197, 399, 513, and 639 cm⁻¹. Distinguished fr…
Rutile (TiO₂)
440–450 cm⁻¹
strong
Eg mode at 447 cm⁻¹ and A₁g mode at 612 cm⁻¹. Distinguished from anatase by the absence of the 144…
Silicon (crystalline)
518–522 cm⁻¹
strong
Sharp peak at 520 cm⁻¹ from the first-order optical phonon. Used as a universal Raman calibration …
Hematite (Fe₂O₃)
220–230 cm⁻¹
strong
Strongest peak near 225 cm⁻¹ (A₁g mode). Additional modes at 245, 292, 410, 498, 611 cm⁻¹. Common …
Magnetite (Fe₃O₄)
660–670 cm⁻¹
strong
A₁g mode near 668 cm⁻¹. Additional peak at 538 cm⁻¹. Distinguishable from hematite by spectral pat…
Feldspar (aluminosilicate)
505–515 cm⁻¹
strong
Strong peak near 510 cm⁻¹ from framework vibrations. Specific position varies with composition (al…
Carbonate (CO₃²⁻) symmetric stretch
1070–1090 cm⁻¹
strong
Symmetric stretch of the carbonate ion. Very strong, sharp peak. Position varies slightly with the…
Biological Molecules
| Assignment | Range (cm⁻¹) | Intensity | Notes | |
|---|---|---|---|---|
Amide I (protein C=O stretch) | 1620–1680 | medium | Protein backbone C=O stretching. Position indicates secondary structure: α-hel… | |
Amide III (protein N-H bend + C-N stretch) | 1230–1300 | medium | Coupled N-H bending and C-N stretching. α-helix ~1300 cm⁻¹, β-sheet ~1235 cm⁻¹… | |
Phenylalanine (ring breathing) | 999–1005 | strong | Sharp peak at 1003 cm⁻¹. The most prominent amino acid peak in protein Raman s… | |
Tryptophan (indole ring) | 755–762 | strong | Indole ring breathing near 759 cm⁻¹. Additional tryptophan markers at 880, 134… | |
Tyrosine (Fermi doublet) | 828–856 | medium | Fermi resonance doublet at 830 and 850 cm⁻¹. The I₈₅₀/I₈₃₀ ratio indicates the… | |
DNA/RNA backbone (PO₂⁻ stretch) | 1080–1100 | medium | Symmetric PO₂⁻ stretch near 1092 cm⁻¹. Marker for nucleic acid phosphodiester … | |
Lipid CH₂ stretch | 2845–2855 | strong | Symmetric CH₂ stretch near 2850 cm⁻¹. Intensity proportional to lipid content.… | |
Carotenoid (C=C stretch) | 1515–1530 | strong | Extremely strong due to resonance enhancement. C=C at 1525 cm⁻¹ and C-C at 115… | |
Collagen (proline/hydroxyproline) | 853–860 | medium | Proline ring vibration near 856 cm⁻¹. Hydroxyproline at 877 cm⁻¹. Key markers … | |
Bone mineral (hydroxyapatite PO₄) | 957–964 | strong | Symmetric PO₄³⁻ stretch at 960 cm⁻¹. The strongest Raman marker for mineralize… |
Amide I (protein C=O stretch)
1620–1680 cm⁻¹
medium
Protein backbone C=O stretching. Position indicates secondary structure: α-helix ~1655 cm⁻¹, β-she…
Amide III (protein N-H bend + C-N stretch)
1230–1300 cm⁻¹
medium
Coupled N-H bending and C-N stretching. α-helix ~1300 cm⁻¹, β-sheet ~1235 cm⁻¹. Useful complement …
Phenylalanine (ring breathing)
999–1005 cm⁻¹
strong
Sharp peak at 1003 cm⁻¹. The most prominent amino acid peak in protein Raman spectra. Intensity us…
Tryptophan (indole ring)
755–762 cm⁻¹
strong
Indole ring breathing near 759 cm⁻¹. Additional tryptophan markers at 880, 1340, and 1552 cm⁻¹.
Tyrosine (Fermi doublet)
828–856 cm⁻¹
medium
Fermi resonance doublet at 830 and 850 cm⁻¹. The I₈₅₀/I₈₃₀ ratio indicates the hydrogen bonding st…
DNA/RNA backbone (PO₂⁻ stretch)
1080–1100 cm⁻¹
medium
Symmetric PO₂⁻ stretch near 1092 cm⁻¹. Marker for nucleic acid phosphodiester backbone.
Lipid CH₂ stretch
2845–2855 cm⁻¹
strong
Symmetric CH₂ stretch near 2850 cm⁻¹. Intensity proportional to lipid content. Used for tissue lip…
Carotenoid (C=C stretch)
1515–1530 cm⁻¹
strong
Extremely strong due to resonance enhancement. C=C at 1525 cm⁻¹ and C-C at 1157 cm⁻¹. Detectable a…
Collagen (proline/hydroxyproline)
853–860 cm⁻¹
medium
Proline ring vibration near 856 cm⁻¹. Hydroxyproline at 877 cm⁻¹. Key markers for connective tissu…
Bone mineral (hydroxyapatite PO₄)
957–964 cm⁻¹
strong
Symmetric PO₄³⁻ stretch at 960 cm⁻¹. The strongest Raman marker for mineralized tissue. Mineral-to…
Solvents & Common Materials
| Assignment | Range (cm⁻¹) | Intensity | Notes | |
|---|---|---|---|---|
Water (O-H bend) | 1630–1650 | weak | Very weak in Raman. Water is an excellent solvent for Raman because it scatter… | |
Ethanol (C-C-O stretch) | 880–885 | strong | C-C-O stretching near 882 cm⁻¹. C-H stretches near 2930 cm⁻¹. Common solvent r… | |
DMSO (S=O stretch) | 1040–1050 | strong | S=O stretch near 1044 cm⁻¹. C-S stretches near 669 and 699 cm⁻¹. Common biolog… | |
Cyclohexane (ring stretch) | 800–802 | strong | Ring breathing at 801 cm⁻¹. Used as a Raman frequency calibration standard alo… | |
Glass (Si-O-Si stretch) | 400–500 | medium | Broad band from amorphous SiO₂ network vibrations. Common substrate interferen… | |
Calcium fluoride (CaF₂) | 320–322 | strong | Single Raman band at 321 cm⁻¹. Preferred substrate for biological Raman — no R… |
Water (O-H bend)
1630–1650 cm⁻¹
weak
Very weak in Raman. Water is an excellent solvent for Raman because it scatters very weakly.
Ethanol (C-C-O stretch)
880–885 cm⁻¹
strong
C-C-O stretching near 882 cm⁻¹. C-H stretches near 2930 cm⁻¹. Common solvent reference.
DMSO (S=O stretch)
1040–1050 cm⁻¹
strong
S=O stretch near 1044 cm⁻¹. C-S stretches near 669 and 699 cm⁻¹. Common biological solvent.
Cyclohexane (ring stretch)
800–802 cm⁻¹
strong
Ring breathing at 801 cm⁻¹. Used as a Raman frequency calibration standard alongside silicon.
Glass (Si-O-Si stretch)
400–500 cm⁻¹
medium
Broad band from amorphous SiO₂ network vibrations. Common substrate interference. Use quartz subst…
Calcium fluoride (CaF₂)
320–322 cm⁻¹
strong
Single Raman band at 321 cm⁻¹. Preferred substrate for biological Raman — no Raman signal in the f…
Gases
| Assignment | Range (cm⁻¹) | Intensity | Notes | |
|---|---|---|---|---|
Nitrogen (N₂ stretch) | 2328–2332 | strong | Sharp peak at 2331 cm⁻¹. Strong Raman scatterer (homonuclear diatomic — Raman … | |
Oxygen (O₂ stretch) | 1554–1558 | medium | Peak at 1556 cm⁻¹. Raman active, IR inactive. Can appear as a weak atmospheric… | |
Carbon dioxide (CO₂ Fermi doublet) | 1285–1388 | strong | Fermi resonance doublet at 1285 and 1388 cm⁻¹. The symmetric stretch of CO₂ is… |
Nitrogen (N₂ stretch)
2328–2332 cm⁻¹
strong
Sharp peak at 2331 cm⁻¹. Strong Raman scatterer (homonuclear diatomic — Raman active, IR inactive).
Oxygen (O₂ stretch)
1554–1558 cm⁻¹
medium
Peak at 1556 cm⁻¹. Raman active, IR inactive. Can appear as a weak atmospheric interference in ope…
Carbon dioxide (CO₂ Fermi doublet)
1285–1388 cm⁻¹
strong
Fermi resonance doublet at 1285 and 1388 cm⁻¹. The symmetric stretch of CO₂ is Raman active (IR in…
Don't want to look up peaks manually? Upload your spectrum to the Raman Peak Identifier and get automated assignments with confidence scores.
Notes on Using This Table
- Raman shift ranges are approximate — exact positions depend on the crystal structure, phase, strain state, temperature, and laser excitation wavelength (for resonance-enhanced modes).
- Relative intensities are qualitative guides. Actual measured intensities depend on the laser wavelength, focusing conditions, sample orientation, and whether resonance enhancement occurs.
- Some entries overlap in wavenumber range. Use additional peaks and context (sample type, other bands present) to distinguish between possible assignments.
- Fluorescence background can obscure weak Raman bands. If you see a rising, curved baseline, consider baseline correction before peak identification.
Related Resources
- How to Read a Raman Spectrum — step-by-step interpretation workflow
- Raman Peak Identifier — automated peak detection and assignment
- Spectral Library Search — match your unknown spectrum against a reference spectra database
- FTIR Functional Group Table — equivalent reference table for infrared spectroscopy
- Spectral File Viewer — view and overlay Raman spectra
Frequently Asked Questions
What is a Raman shift table?
A Raman shift table is a reference chart listing the characteristic Raman scattering frequencies (in cm⁻¹) for common functional groups, materials, and compounds. It helps spectroscopists identify unknown materials by matching observed peak positions to known assignments. Unlike IR correlation tables, Raman tables emphasize symmetric vibrations and polarizable bonds.
Why are some Raman peaks strong and others weak?
Raman peak intensity depends on the polarizability change during the vibration. Symmetric stretches of highly polarizable bonds (C=C, S-S, aromatic rings, C≡C) produce the strongest Raman bands. Asymmetric stretches and vibrations of polar bonds (O-H, N-H) are typically weak in Raman but strong in IR. This complementarity is why Raman and IR are often used together.
What is the silicon peak used for in Raman spectroscopy?
Crystalline silicon produces a sharp, intense Raman peak at 520.7 cm⁻¹ that is used as a universal calibration standard for Raman spectrometers. The peak position is precisely known and reproducible. In semiconductor research, shifts from 520.7 cm⁻¹ indicate mechanical stress or strain in the silicon crystal.