Jabłoński Diagram

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A Jablonski diagram showing the excitation of molecule A to its singlet excited state (1A*) followed by intersystem crossing to the triplet state (3A) that relaxes to the ground state by phosphorescence.

In molecular spectroscopy, a Jablonski diagram is a diagram that illustrates the electronic states of a molecule and the transitions between them. The states are arranged vertically by energy and grouped horizontally by spin multiplicity. Nonradiative transitions are indicated by squiggly arrows and radiative transitions by straight arrows. The vibrational ground states of each electronic state are indicated with thick lines, the higher vibrational states with thinner lines.[1] The diagram is named after the Polish physicist Aleksander Jabłoński.[2]

1 Transitions

Radiative transitions involve the absorption, if the transition occurs to a higher energy level, or the emission, in the reverse case, of a photon. Nonradiative transitions arise through several different mechanisms, all differently labeled in the diagram. Relaxation of the excited state to its lowest vibrational level is called vibrational relaxation. This process involves the dissipation of energy from the molecule to its surroundings, and thus it cannot occur for isolated molecules. A second type of nonradiative transition is internal conversion (IC), which occurs when a vibrational state of an electronically excited state can couple to a vibrational state of a lower electronic state. A third type is intersystem crossing (ISC); this is a transition to a state with a different spin multiplicity. In molecules with large spin-orbit coupling, intersystem crossing is much more important than in molecules that exhibit only small spin-orbit coupling. This type of nonradiative transition can give rise to phosphorescence.

A Jablonski diagram representing Förster resonance energy transfer (FRET)

2 External links

[1] Kasha, Michael. "From Jablonski to femtoseconds. Evolution of molecular photophysics." Acta Physica Polonica-Series A General Physics 95.1 (1999): 15-36.[1]

[2] Szudy, Józef. "Aleksander Jabłoński and the Brothers Vavilov on the 80th anniversary of the formulation of the Jabłoński diagram, 70th anniversary of the death of Nicolai Ivanovich Vavilov, and 62nd anniversary of the death of Sergei Ivanovich Vavilov." NAUKA 4 (2012).[2]

[3] Nickel, B. "From Wiedemann's Discovery to the Jablonsky Diagram. A Documentation, Dedicated to the Memory of J. Perrin, P. Pringsheim, SI Vavilov, VL Levshin, and F. Perrin." EPA NEWSLETTER-EUROPEAN PHOTOCHEMISTRY ASSOCIATION (1998): 19-72.

[4] Smentek L (2009) Different sides of the Jabłoński Diagram on its 75th anniversary. Newsletter of the Forum on International Physics, American Physical Society, June 2009.[3]

[5] Kawski, A. "The research work of Alexander Jabłoński (1898-1980) and its impact on further development of photoluminescence in solution." EPA Newslett 61 (1997): 17-26.

[6] Nickel, B. "From the Perrin Diagram to the Jablonski Diagram. Part 2." EPA Newsletter-European Photochemistry Association (1997): 27-60.
  1. Elumalai, P., Atkins, P., de Paula, J. Atkins' Physical Chemistry, Oxford University Press, 2002. Template:ISBN
  2. Jabłoński, Aleksander "Efficiency of Anti-Stokes Fluorescence in Dyes" Nature 1933, volume 131, pp. 839-840. Template:Doi