In general, atoms within a single molecule are not quantum entangled with each other solely because they are interacting with each other. Quantum entanglement is a unique phenomenon that occurs when two or more particles become correlated in such a way that their quantum states are inseparable, even when physically separated.
While the atoms within a molecule interact with each other through various chemical bonds, these interactions do not necessarily lead to quantum entanglement. The behavior of atoms within a molecule can be described by molecular orbital theory, which provides a way to understand the distribution of electrons and the chemical properties of the molecule. In this framework, the interactions between atoms are typically described by covalent, ionic, or other types of bonding, which involve the sharing, donating, or receiving of electrons.
Quantum entanglement is more commonly observed in situations involving isolated particles or systems that have been specially prepared to exhibit entanglement. It is a property that arises from the fundamental principles of quantum mechanics, such as superposition and measurement entanglement. While entanglement can occur between different particles or subsystems, it does not generally arise simply from the interactions between atoms within a single molecule.