Application of Fluorescence Spectroscopy

Fluorescence spectra belongs to the emission spectrum. Compound absorbs energy to transit from the ground state to the excited state, then releases the energy in a non-radiative manner to relax to the minimum point of the excited state energy, and then de-excites to the ground state by releasing photons. This is a process of de-excitation from the minimum point of excited-state energy to the ground state, so the fluorescence wavelength can be predicted by finding the minimum point of excited-state energy. The prediction of fluorescence spectra through computational chemistry is a new field of study attempting to discover a more systematic and inexpensive method of producing fluorescent dyes. Reliable and accurate methods of predicting fluorescence spectra of highly complex molecules has been found by utilizing different levels of semi-empirical theory to simulate spectra.

Application of Fluorescence Spectroscopy

Fluorescence spectroscopy has been used in various fields, especially in non-destructive, microscopic, chemical analysis and imaging analysis. Fluorescence analysis can quickly provide qualitative or quantitative data.

Nanotechnology: nanocrystals and nanotubes.

Biology/Life science: the characterization of photoreceptors, the molecular mechanism of proton transport across membranes, and the complex microenvironment of molecules.

Display technology: OLED.

Carbon Nanotubes: nanomaterials.

Water environment: solubility of organic matter.

Food: gas sensors.

Drugs: bioactivity of configuration, protein interaction, fluorescence immunoassay.

Fluorescence Spectrum Prediction Workflow

1. Customers provide the structure of the compound for which the fluorescence spectrum needs to be calculated.

2. 3D structure generation and optimization

Gauss View

We use Gauss View to build a 3D structure, and small basis set is applied to optimize the ground state. A high-quality initial structure can be obtained by using a large basis set in time-dependent density functional theory (TD-DFT) calculations.

OMEGA

Our experts generally use OMEGA for large-scale compound calculations. We apply OMEGA software to generate high-quality 3D structure utilizing 1D SMILES code and perform conformation search, and the global minimum point conformation is used for TD-DFT calculation.

CONFLEX

We use CONFLEX to search for the conformation of the compound comprehensively, and calculate the conformational distribution. Conformation of the compound in aqueous solution can be obtained, and we use the conformation with the smallest Gibbs free energy for the TD-DFT calculation.

3. TD-DFT calculation

TD-DFT calculation is performed for structural optimization after obtaining the initial conformation.

4. Analysis of calculation results

We conduct the identification of the calculated wavelength of the last excited state according to the calculation results.

Protheragen-ING's Advantages

At Protheragen-ING, various basis sets are available for structure optimization such as cam-B3LPY/6-31+g(d), cam-B3LPY/6-31+g(d) and so on.

Our experts have rich experience in the calculation of excited states and electronic spectra.

Fluorescence spectrum prediction provides fluorescence spectra of highly complex molecules using TD-DFT calculation method. Our fluorescence spectrum prediction services remarkably reduce the cost, promote further experiments, and enhance the understanding of chemical process for customers worldwide. 

Reference

Liu, C.; et al. Graphitic carbon nitride nanosheets as a multifunctional nanoplatform for photochemical internalization-enhanced photodynamic therapy. Journal of Materials Chemistry B. 2018, 6(47): 7908-7915.