Quantum trembling: Why there are no truly flat molecules
Phys.org
February 20, 2026
AI-Generated Deep Dive Summary
Chemistry textbooks often portray molecules as rigid and flat structures, such as formic acid (methanoic acid) being depicted as a two-dimensional sheet. However, quantum physics reveals a more dynamic reality: molecules are inherently three-dimensional due to the constant motion of atoms at the smallest scale, even in what appears to be the simplest structures. This movement, known as zero-point motion, is a fundamental aspect of quantum mechanics that prevents molecules from being perfectly flat or static.
The rigid, two-dimensional model of molecules like formic acid is an oversimplification. In reality, molecular structures are influenced by forces such as thermal vibrations and electronic repulsion, which cause atoms to constantly shift positions. This phenomenon, rooted in Heisenberg’s Uncertainty Principle, means that even the most seemingly flat molecule exists in a state of flux, occupying space in three dimensions rather than being confined to a single plane.
Understanding this quantum trembling is crucial for advancements in chemistry and related fields. It challenges traditional assumptions about molecular rigidity and highlights the importance of considering molecular flexibility in applications like drug design and materials science. This knowledge not only deepens our understanding of molecular behavior but also has practical implications for how we approach chemical reactions, molecular interactions, and the development of new compounds.
In summary, while textbooks may simplify molecules as flat and static, quantum physics paints a more accurate picture: molecules are dynamic, three-dimensional entities that resist rigidity. This realization underscores the importance of embracing complexity in molecular structures and opens up new avenues for scientific exploration and innovation.
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Originally published on Phys.org on 2/20/2026