Laser-induced fluorescence of free diamondoid molecules

Abstract

aWe observe the fluorescence of pristine diamondoids in the gas phase, excited using narrow band ultraviolet laser light. The emission spectra show well-defined features, which can be attributed to transitions from the excited electronic state into different vibrational modes of the electronic ground state. We assign the normal modes responsible for the vibrational bands, and determine the geometry of the excited states. Calculations indicate that for large diamondoids, the spectral bands do not result from progressions of single modes, but rather from combination bands composed of a large number of Dv = 1 transitions. The vibrational modes determining the spectral envelope can mainly be assigned to wagging and twisting modes of the surface atoms. We conclude that our theoretical approach accurately describes the photophysics in diamondoids and possibly other hydrocarbons in general.

Spectroscopic Characterization of the Product Ions Formed by Electron Ionization of Adamantane

“…[15][16][17] Estimates suggest that diamondoids may comprise 1-3 % of the total cosmic carbon budget. [20][21] Infrared and Raman spectra of neutral and cationic diamondoids have been measured and compared with Density Functional Theory (DFT) computed spectra. The ionization potentials of the first five members of the diamondoid family and the electronic structure of a series of diamondoids have been investigated by valence photoelectron spectroscopy.…”

Nanotechnology of diamondoids for the fabrication of nanostructured systems

“…Adamantanes show broad luminescence energy from 4.9 to 6.5 eV due to the recombination of the self-trapped excitons. UV laserinduced fluorescence of gas-phase higher diamondoids has also been reported recently [79].…”

The origin of the solvent dependence of fluorescence quantum yields in dipolar merocyanine dyes

“…The ability to uoresce is usually linked to a rigid, conjugated molecular structure which ensures that the excited state has a stable minimum. [5][6][7] If the emissive geometry differs only little from the ground-state geometry, sharp and structured absorption and emission spectra are observed, which are approximately mirror images of each other. 5 In contrast to that, non-uorescent chromophores have reactive excited states and decompose or decay to the ground state non-radiatively before a photon can be emitted.…”

“…The detailed calculation of the friction constants g is given in the ESI. ‡ The approach based on eqn (5), (6) and (8) is one of the simplest models that can be used to rationalize the photoluminescence quantum yields and can predict qualitative trends based on temperature and solvent environment including the viscosity and solvatochromic shis.…”