Category archives: DIPC Computational and Theoretical Chemistry

Ever since the birth of quantum mechanics in the early twentieth century, chemists have struggled with a fundamental paradox. On one hand, Lewis dot structures and molecular drawings teach us to think of electrons as localized entities—either sitting neatly in lone pairs or shared directly between two bonding atoms. On the other hand, Schrödinger’s wave […]

Chemical bonds are among the most familiar ideas in science. They explain why hydrogen and oxygen combine to form water, why carbon atoms build long chains in organic molecules, and why every substance has the shape and properties it does. Yet, despite their central role in chemistry, bonds are not directly observable objects. They are […]

Pressure is usually imagined as a force that simply squeezes matter into a smaller space. At the molecular level, however, the story is more subtle. A recent computational chemistry study explored how pressure changes the shapes of molecules and the fleeting structures known as transition states, which appear briefly as reactions occur. The work focused […]

When we think of atoms sitting on a surface, we tend to imagine them as fairly still, especially at very low temperatures (colder than liquid nitrogen, in fact). Yet in modern surface science we often discover the opposite: atoms can be surprisingly restless, gliding from place to place in ways that shape how materials grow […]

Quantum computers promise to change how we calculate the behavior of electrons in molecules, but for the machines we have now — noisy, limited in size and coherence — the challenge is to squeeze the most chemistry out of the least quantum hardware. Now, a new paper introduces a practical trick to do exactly that: […]

Protein molecules consist of one or several long chains of aminoacids (usually between and 300 units) called polypeptides – a peptide is an organic compound comprising two or mores aminoacids – linked in a characteristic sequence. This sequence is called the primary structure of the protein. These polypeptides may undergo coiling or pleating, the nature […]

The development of luminescent organic radicals has resulted in materials with excellent optical properties for near-infrared (NIR) emission, like organic light-emitting diodes (OLEDs). Light generation in this range could be used for healthcare diagnosis and treatment to surveillance, communications and other security applications. Although an external quantum efficiency greater than 20% in electroluminescence has been […]

As early as the 1970s, it was suggested that one-particle reduced density matrix functional theory could be an attractive alternative formalism to wave function-based methods. Unfortunately, calculations based on exact functionals generated by the constrained-search formulation are computationally too expensive, which has prompted the development of approximate functionals for practical applications. The functionals currently in […]

Light emission (fluorescence or phosphorescence) in organic molecules, in the vast majority of cases, proceeds from the lowest energy excited state irrespective of the excitation energy used. This is known as the Kasha’s rule, which states that most of the molecules are emissive from the lowest energy, same (ground state) spin multiplicity, S1 excited state […]

Nonlinear optics is concerned with the optical properties of matter subjected to intense electromagnetic fields. For nonlinearity to manifest itself, the external field should not be negligible compared to the internal fields of atoms and molecules of which the matter consists. Lasers are capable of generating external fields sufficiently intense for nonlinearity to occur. Actually […]