## What Is Density Functional Theory?

Among a variety of first-principles theoretical calculations and simulation methods, density functional theory is attractive for its computational efficiency and universal applicability. It has been integrated into a variety of quantum chemical calculation software and is easy to be used by researchers in professional fields. The core of the DFT method is to use the electron density as the carrier of all information in the ground state of the molecule (atom), rather than the wave function of a single electron. In this way, the multi-electron system problem is transformed into an easy-to-solve single-electron problem. Nowadays, DFT has emerged as a powerful tool for computational study of chemical reactions. DFT calculations of heterogeneous reactions on catalyst surfaces can provide valuable insights about the reactivity and mechanisms, allowing *in silico* screening and design of catalysts.

Figure 1. Density functional theory calculation for the coordination of THF to (a) [Br-Cu-Br]^{-} anion and (b) [nBu-Cu-nBu]^{-} anion. (Heravi, M. M.; *et al*.)

## Our Methodologies for DFT Calculation

### Local density approximation (LDA)

LDA method is suitable for calculating systems with a small rate of change in electron density. We apply it in the calculation of metal energy bands and semiconductor energy bands.

### Generalized gradient approximation (GGA)

Compared with LDA, GGA has a wider range of applications. We use GGA to conduct accurate calculation by optimizing semiconductor and metal lattice constants.

### Hybrid density functional (HDF)

In addition to the two basic functional forms of LDA and GGA, HDF incorporates the Hatree-Fock exchange effect into the exchange correlation term in a hybrid way. We apply the hybrid density functional in the calculation of organic chemistry, such as the calculation of chemical reaction mechanism, *etc*.

## Applications of Our DFT Calculation

- Construct models according to the reaction mechanism of the reactive intermediates of each reactant and the transition states that may be involved.
- Optimize structures of these models to calculate corresponding energy including reaction enthalpy, activation energy and other important information.
- Analyze the reaction path (the process of evolving from the transition state to the reactant and reactive intermediate respectively).

## Our DFT Calculation Services

At Alfa Chemistry, we can use DFT to optimize the structure of reactants, products and transition states of various reaction types, and calculate the thermodynamic and kinetic parameters of each reaction pathway at different temperatures. Our density functional theory calculation services include the following:

### Calculation of reaction enthalpy

The enthalpy of reaction is one of the important criteria for the thermodynamic feasibility of chemical reactions. Our teams provide crucial data such as the reaction energy barrier and reaction enthalpy by calculating the transition state of each reaction step.

### Calculation of activation energy

We calculate the active intermediate and transition state separately, and determine the theoretical activation energy value based on the relative energy.

### Determine the transition state

The reactive intermediate is closely related to the transition state, and the transition state of the reactive intermediate is determined through the analysis of the reaction path.

### Consider the influence of solvent, zero point energy, temperature, *etc*.

Correction of vibration energy can be achieved with the use of zero-point energy.

When the reaction is carried out in an aqueous solution, the influence of the solvent cannot be ignored. It's necessary to add the solvent effect in the calculation.

When there are molecules that vibrate, translate and rotate in the reaction, the effect of temperature on the reaction is also considered.

Density functional theory calculation provides an effective way to optimize the chemical process. Our density functional theory calculation services remarkably reduce the cost, promote further experiments, and enhance the understanding of chemical process 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!

Reference

- Yi, H.;
*et al*. Unravelling the hidden link of lithium halides and application in the synthesis of organocuprates.*Nature Communications*. 2017, 8: 14794.