The Aragonite Raman spectrum and its interpretation are presented below.
Aragonite sample data
|Description:||Aragonite mineral sample|
|Source:||Grigore Cobălcescu Museum|
|Owner:||Department of Geology – Alexandru Ioan Cuza University of Iasi|
Aragonite sample image
Main Raman bands of Aragonite
|Wavenumbers (cm-1):||1083vs, 701w, 250m|
|Instrument settings:||Raman spectrograph HE 532nm (Horiba Jobin-Yvon)|
|Spectral resolution:||2 cm-1|
|Conditions of measurement:||at room temperature|
Interpretation of Raman spectrum of Aragonite
The characteristic Raman band due to the external vibration mode (M-CO3) at 250 cm-1, and the ν1 internal mode (symmetric stretching) at 1083 cm-1 are easily distinguished. In the Raman spectrum of the aragonite sample don’t have values below 200 cm-1 because the spectral range is between 200-3400 cm-1.
In case of aragonite only four bands out of the 30 predicted Raman-active modes (Urmos et al., 1991) were detected in the Raman spectra of the aragonite sample no. 5473. This spectrum is governed by the very strong Raman line (1083 cm-1) atributed to the ν1 symmetric stretching mode of the carbonate group. The ν4 mode of CO3 has values at 701 cm-1. The ν2 vibration mode is not observed in this study; ν3 vibration are observed at 1461 and 1573 cm-1.
The frequencies of all Raman bands observed in Aragonite, Strontianite and Witherite can be corelated with the atomic masses of the cations (Buzgar and Apopei, 2009).
|Buzgar and Apopei, 2009||Urmos, 1991||Krishnamurti, 1960||Assignment|
|ν4 symmetric deformation|
|NO||853||854||ν2 asymmetric deformation|
|1083||1085||1086||ν1 symmetric stretch|
|ν3 asymmetric stretching|
NO = not observed; NA = not assigned.
References for the Raman spectrum of Aragonite
- BUZGAR N., APOPEI A. I. (2009) – The Raman study on certain carbonates. Analele Stiintifice ale Universitatii “Al. I. Cuza” – Iasi, Tome 55, issue 2, 97-112 [link]
- URMOS J., SHARMA S. K., MACKENZIE F. T. (1991) – Characterization of some biogenic carbonates with Raman spectroscopy. American Mineralogist, 76, p. 641-646 [link]
- KRISHNAMURTI D. (1960) – The Raman spectra of aragonite, strontianite and witherite. Indian Academy of Sciences [link]