P 246 - Spectra of ultra-weak photon emission

Abstract

Organisms undergoing oxidative metabolism or stress chemically generate electronically excited species through dioxetane and tetroxide pathways. Consequently, luminescence is emitted which could be exploited for non-invasive label-free monitoring of oxidative stress. Spectral analysis of this endogenous chemiluminescence can serve as a tool for identification of the emitters as products of oxidation. Here we employ quantum mechanical calculations and sensitive photon counting methods to obtain deeper understanding of the emitter molecules both from theoretical and experimental perspective. We focused on the analysis of carbonyl groups of simple model species (formaldehyde, acetone, etc.) and carbonyls formed by fragmentation of linoleic acid since they are common product of oxidation and also one of major emitters of endogenous chemiluminescence. We calculated emission spectra of carbonyl groups using TURBOMOLE code for quantum mechanical calculations. We used TDDFT method for excitation and emission and DFT method for optimization of the ground state. The generalized gradient approximation of Perdew, Burke and Ernzerhof (PBE) were chosen for the exchange correlation density functional. We used def2-SV(P) as basis set and the corresponding Coulomb fitting bases. We found emission spectra of individual carbonyls in water environment and in vacuum.