Spectroscopy is not only an important method to characterize the optical properties of materials, but also a powerful tool to probe the structure of materials. Predicting the spectrum from the material structure is a common computing requirement. Different calculation methods are applied based on different light wavebands and spectral response principles. Common spectra include: electronic spectroscopy, infrared spectroscopy, Raman spectroscopy, nuclear magnetic resonance spectroscopy, and so on. Alfa Chemistry is equipped with advanced and highly reliable Density functional theory, Density-functional based Tight-Binding (DFTB), ForceField and other basic calculation engines. In addition, we also support advanced electron-phonon coupling models to simulate various spectroscopic properties of materials. Our diverse powerful modeling tools can directly construct the structure of various materials (molecules, crystals, polymers), etc., and calculate a series of parameters. Our high-quality graphics drawing tools and detailed data perspective analysis tools help to accelerate your spectroscopic property prediction process.
Application of Spectroscopic Property Prediction
- Identify a substance and determine its chemical composition
- Study the structure and properties of matter
- Predict material properties and assist in microstructure characterization
Figure 1. DFT synthesis and characterization of NHC-modified Au11 nanoclusters. a, Structure of NHC precursors employed in this study featuring a variety of organic substituents on the nitrogen atoms flanking the key carbon. b, Reaction of undecagold cluster [Au11(PPh3)8Cl2]Cl (2) with NHC precursors. c, Mass spectrometric characterization of the reaction mixture leading to [Au11(PPh3)8Cl2]Cl. d, Mass spectrometric characterization of the reaction of 1b with 2, showing a mixture of 3b and 4b along with DFT-predicted structures. (Narouz, M. R.; et al. 2019)
With the deepening of quantum chemistry research and the improvement of computing software, they play an important role in the process of scientific research and chemistry teaching. We apply multiple quantum chemistry computing software to simulate and analyze the three-dimensional structure and electronic orbit of organic molecules and predict organic matter. To make it easier and better for researchers, Alfa Chemistry provides practical spectroscopic property prediction in a competitive fashion. We have prepared the most convenient services for you.
- Electronic Circular Dichroism (ECD) Simulation Prediction
- EPR/ESR Simulation Prediction
- Fluorescence Spectrum Prediction
- IR Spectrum Prediction
- NMR Spectrum Prediction
- ORD Simulation Prediction
- Phosphorescence Spectrum Prediction
- ROA Prediction
- Specific Rotation Calculation
- UV-Vis Spectrum Prediction
- Vibration Circular Dichroism (VCD) Spectrum Prediction
- Raman Spectrum Prediction
In order to determine the absolute configuration (AC) of natural products, Alfa Chemistry has developed an efficient time-dependent density functional theory (TD-DFT) method to calculate and predict the ECD spectrum of medium-sized molecules in a short time, which provides crucial information on the three-dimensional structure of chiral molecules.
Nowadays, electron paramagnetic resonance or electron spin resonance spectroscopy technology is applied to study the structure, dynamics and spatial distribution of substances containing unpaired electrons. Our groups are capable of carrying out the prediction of EPR spectra from single dynamical trajectories generated from density functional theory and molecular dynamics simulations.
Reliable and accurate methods of predicting fluorescence spectra of highly complex molecules have been developed with multiple semi-empirical theory to simulate spectra. At Alfa Chemistry, our scientists apply time-dependent density functional theory (TD-DFT) calculations to optimize the structure and predict the fluorescence spectrum.
IR spectrum has been widely applied for the identification of chemical bonds or functional groups. We provide rapid and accurate IR spectrum prediction services using various computational methods such as ab initio molecular dynamics, machine learning and DFT method.
At Alfa Chemistry, we support various NMR spectrum prediction including 1H-NMR spectrum, 13C-NMR spectrum and so on. We can calculate properties of molecules including NMR shifts accurately and rapidly. Our advanced machine learning-based prediction and DFT calculation methods are available for providing NMR spectrum, assisting in the structure identification.
Optical rotation dispersion (ORD) are widely used to distinguish the structure of different conformations and determine the position of substituents in macromolecules such as steroids. Our experts have professional knowledge and rich experience in the field applied molecular dynamics computer simulation, ab initio calculations, time dependent density functional theory and QM/FQ/PCM approach to perform calculation of chiroptical properties and spectroscopies by predicting ORD curves.
Nowadays, phosphorescent materials have long triplet life, and are able to effectively avoid the interference of short-lived background fluorescence of organisms. We have established linear response model and state-specific model to calculate the phosphorescence spectrum, providing the corresponding radiative rate constant and intersystem crossing (ISC) rate constant.
Alfa Chemistry provides comprehensive Raman optical activity (ROA) prediction services to deliver a wealth of important information about both structure and conformational dynamics, such as tertiary folding and secondary structure of proteins and nucleic acids.
As an essential physical constant of optically active substances, specific rotation has been applied to distinguish drugs or determine the content and purity of drugs. We are able to determine the absolute configuration of the molecule by calculating the specific optical rotations of the two chiral molecular configurations.
Scientists use ultraviolet-visible spectroscopy (UV-Vis) spectrum to identify compound, determine purity and isomers, and perform quantitative analysis. We mainly apply time-dependent density functional theory (TD-DFT) calculation to predict the UV-Vis spectrum in which dominant wavelength is determined.
Figure 2. DFT and UV-vis spectroscopic prediction of structure for NHC-modified nanoclusters. a, Labelling of phosphines in [Au11(PPh3)8Cl2]Cl (2) and exchange with1a. b, DFT-predicted changes in potential energy for reaction shown in a at each phosphine. c, Comparison of calculated optical spectra (red, blue, green curves) of cluster 3a to experimental data (black). (Narouz, M. R.; et al. 2019)
VCD spectrum technology has been widely applied to accurately predict chirality through conformational search and quantum chemical calculations, Alfa Chemistry are capable of providing prediction of VCD spectra using ab initio density functional theory for the determination of the absolute configurations and conformations of chiral molecules.
The basis of Raman spectroscopy is the interaction of light with the chemical bonds of matter. Inference from Raman spectra can provide detailed information about chemical structure, polymorphism, crystallinity, and molecular dynamics. To simulate Raman spectroscopy, Alfa Chemistry creates and uses computational techniques based on the principles of quantum chemistry. Raman scattering simulation technology can be roughly divided into static technology and dynamic technology according to the degree of environment they cover.
- Flexible and advanced computational methods
- Personalized and customized innovative scientific research services
- Cost-efficient and time-saving
Spectroscopic property prediction provides an effective way to calculate various spectra and spectral characteristics. Our spectroscopic property prediction services remarkably reduce the cost, promote further experiments, and enhance the understanding of catalytic reactions for customers worldwide. Our personalized and all-around services will satisfy your innovative study demands. If you are interested in our services, please don't hesitate to contact us. We are glad to cooperate with you and witness your success!
- Narouz, M. R.; et al. N-heterocyclic carbene-functionalized magic-number gold nanoclusters. Nature Chemistry. 2019.