Table 2.1.

Basic difference between molecular mechanics and quantum mechanics.

Characteristics	Molecular mechanics	Quantum mechanics
State of the molecule	Frozen at 0 K in vacuum	Neither frozen nor in vacuum
Electronic nature of atom	Not taken into consideration	Considered
Structural vibrations Influence of the medium	Not taken into consideration	Considered
Total energy	Based on classical physics (sum of all attractive and repulsive forces)	Based on Schrodinger wave equation and Born-Oppenheimer approximation
Computational power	Less	More
Computational time	Less	More
Accuracy	Less	More