Guanine This page summarizes the optical absorption and emission data of Guanine that is available in the PhotochemCAD package, version 2.1a (Du 1998, Dixon 2005). I reworked their data to produce these interactive graphs and to provide direct links to text files containing the raw and manipulated data. Although I have tried to be careful, I may have introduced some errors; the cautious user is advised to compare these results with the original sources.

You can resize any of the graphs by clicking and dragging a rectangle. If you hover the mouse over the graph, you will see a pop-up showing the coordinates. One of the icons in the upper right corner will let you export the graph in other formats.


This optical absorption measurement of Guanine were made by R.-C. A. Fuh on 06-24-1997 using a Cary 3. The absorption values were collected using a spectral bandwidth of 1.0 nm, a signal averaging time of 0.133 sec, a data interval of 0.25 nm, and a scan rate of 112.5 nm/min.

These measurements were scaled to make the molar extinction coefficient match the value of 10,700cm-1/M at 243.0nm (Fasman, 1975).

Original Data | Extinction Data


Due to the expected low fluorescence yield, estimated to be 0.0003 (Callis, 1979) a fluorescence spectrum was not collected. For fluorescence studies of the nucleic acid bases and related heterocyclic compounds, see (Longworth, 1966).


Callis, P. R. (1979) Polarized fluorescence and estimated lifetimes of the DNA bases at room temperature. Chem. Phys. Lett. 61, 563-567.

Dixon, J. M., M. Taniguchi and J. S. Lindsey (2005), "PhotochemCAD 2. A Refined Program with Accompanying Spectral Databases for Photochemical Calculations, Photochem. Photobiol., 81, 212-213.

Du, H., R.-C. A. Fuh, J. Li, L. A. Corkan and J. S. Lindsey (1998) PhotochemCAD: A computer-aided design and research tool in photochemistry. Photochem. Photobiol. 68, 141-142.

Fasman, G. D., Editor (1975) Handbook of Biochemistry and Molecular Biology, 3rd Edition, Nucleic Acids, Volume I, pp. 65-215, CRC Press, Cleveland, Ohio.

Longworth, J. W., R. O. Rahn and R. G. Shulman (1966) Luminescence of pyrimidines, purines, nucleosides and nucleotides at 77 °K. The effect of ionization and tautomerization. J. Chem. Phys. 45, 2930-2939.