NOP Analysis Service

The concept of natural orbit was first proposed by Per-Olov Löwdin in 1955 to describe the unique set of orthogonal 1-electron functions inherent in the N-electron wave function. In quantum chemistry, the natural bond orbital or NBO is the calculated bond orbital with the largest electron density.
Atomic orbital→NAO→NHO→NBO→NLMO→Molecular orbital

Natural (local) orbitals are used in computational chemistry to calculate the distribution of electron density in and between atoms. They have "maximum occupancy characteristics" in the local 1 center and 2 center regions of the molecule. The natural bond orbital (NBO) contains the highest possible electron density percentage, which is ideally close to 2.000, thus providing the most accurate "natural Lewis structure" of ψ. The high percentage of electron density (expressed as %-ρL) is usually greater than 99% in common organic molecules, which corresponds to the precise natural Lewis structure. 

What is the Lewis structure?

Using a computer program that can calculate NBO, the best Lewis structure can be found. The best Lewis structure can be defined as the structure with the largest amount of charge (Lewis charge) on the Lewis orbit. The small electron charge in the Lewis orbit indicates that the electron delocalization is strong. In the resonant structure, there may be primary and secondary contributing structures. For example, for amides, NBO calculations indicate that the structure with a carbonyl double bond is the predominant Lewis structure. However, in the NBO calculation, since the bond polarity effect is included in the resonance structure, "covalent ion resonance" is not required. This is similar to other modern valence bond theory methods.

Overall solutions

• Through NBO analysis, CD ComputaBio can easily find out the number of atoms in the calculated molecule, the type and composition of various molecular orbitals, and the intramolecular and intermolecular superco-interactions.
• The population of natural atomic orbitals (occupation number) in CD ComputaBio's NBO analysis is obtained by the eigenvalues of the single-center angular symmetric density matrix block under the constructed NAO base; the population of natural molecular orbitals (occupation number) ) is the corresponding eigenvalue of the angularly symmetric density matrix block after block diagonalization, and its physical meaning is the number of electrons in the natural atomic orbital or molecular bond orbital.
• The natural bond orbital can be used to analyze the bond formation in the molecule.

Services items

CD ComputaBio's natural bond orbital analysis (NBO) service can reduce the cost of subsequent experiments. Natural bond orbital analysis (NBO) service is a personalized and customized innovative scientific research service. Before determining the corresponding analysis plan and price, each project needs to be evaluated. If you want to know more about service prices or technical details, please feel free to contact us. If you want to know more about service prices or technical details, please feel free to contact us.