An alternative method of calculation has been developed by physicist Tárcius Nascimento Ramos and his team to reduce the time required for computer simulation of absorption spectra. The method, known as INDO/S (Intermediate Neglect of Differential Overlap with Spectroscopic Parameterization), offers a more efficient and cost-effective approach compared to the currently dominant density functional theory (DFT) method.
Simulation is an essential tool in studying molecules with high probabilities of absorbing low-energy photons. These molecules have a wide range of applications, including high-resolution microscopy, data storage, and medicinal treatments. However, simulating large molecules requires significant computational power, often taking days or even months to process.
The INDO/S method, although considered approximative in nature, proved to be highly efficient in theoretical studies of large molecular compounds. By replacing computationally costly calculations with tabulated values derived from experimental spectroscopic data, the method significantly reduced calculation time to approximately four hours on a conventional computer.
Ramos and his team used the INDO/S method to study the one- and two-photon absorption spectra of a large molecule derived from stilbene. The molecule, consisting of over 200 carbon, oxygen, and hydrogen atoms, presented unique challenges due to its flexibility and shape-changing properties.
By characterizing the absorption spectra of these molecules at a microscopic level, the researchers found that the semi-empirical INDO/S method was most suitable for predicting the absorption properties of large molecules in solution. These findings have important implications for molecular engineers seeking to develop novel compounds with greater efficiency in various applications.
One of the key advantages of two-photon absorption is its high spatial resolution, making it suitable for microscopy imaging of deep tissues with minimal damage to surrounding structures. Additionally, two-photon absorption enables the creation of precise 3D structures for data storage purposes with high-density encoding per volume.
This study represents a significant step forward in the field of computer modeling of absorption spectra and opens up new possibilities for computational investigations of complex molecular systems.
Sources:
– The Journal of Chemical Physics
– Agência FAPESP