Question

Repeat the above calculations using the B3LYP hybrid functional. How do these energies compare to those from experimentation and from DFT with the PBE functional? Does the computation time with the B3LYP change? Explain why or why not.

a) Lower energies; faster computation
b) Higher energies; slower computation
c) Higher energies; faster computation
d) Lower energies; same computation time

Answer 1

The B3LYP hybrid functional is commonly used in computational chemistry. It provides accurate energies compared to the PBE functional, but this can vary depending on the system. Computation time with B3LYP can be similar to or slightly slower than PBE.

Step-by-step explanation:

The B3LYP hybrid functional is a commonly used method in computational chemistry that combines the Becke three-parameter exchange functional (B3) and the Lee, Yang, and Parr correlation functional (LYP). When using the B3LYP functional for calculations, the energies obtained can be compared to those from experimental measurements and from calculations using the PBE functional.

It is important to note that the comparison of energies between computations and experiments can vary depending on the specific system being studied. In general, the B3LYP functional tends to provide more accurate energies compared to the PBE functional, but this is not always the case.

In terms of computation time, the B3LYP functional can have similar or slightly slower computation times compared to the PBE functional. The exact computation time can depend on the specific system being studied and the computational resources available.