physics – Andrew Kortyna

Ab Initio Molecular Dynamics

A graduate of Wesleyan University with a PhD in physics, Andrew Kortyna is a former assistant professor of physics at Lafayette College. Andrew Kortyna has conducted research on the scattering of ultralow-energy electrons with molecules using laser-based techniques. He is also experienced in using computational packages, such as the Gaussian ab initio molecular structure computational package, to perform molecular analysis.

Molecular dynamics have helped scientists gain insight into how molecules behave in reactions at a microscopic level. Over time, scientists have devised a number of techniques to help study molecular dynamics in reactions. Recently, a technique known as ab initio molecular dynamics (AIMD) was developed. This technique provides a realistic real-time simulation of complex molecular systems and has been used by many molecular physicists and chemists to study molecules.

Ab initio molecular dynamics differs from traditional molecular dynamics techniques in a variety of ways. Unlike traditional molecular dynamics that rely on classical Newtonian dynamics, ab initio molecular dynamics is based on the Schrodinger equation. This makes it more precise when handling and evaluating quantum effects. In addition, ab initio molecular dynamics uses more practical physical potentials for studying quantum effects. Its traditional counterpart uses less empirical potentials to approximate quantum effects, which is less precise.

Bose-Einstein Condensate

Andrew Kortyna works at the Joint Institute of Laboratory Astrophysics at the University of Colorado in Boulder, Colorado. There, he serves as a research associate. Previously, Andrew Kortyna worked at Colby College in Waterville, Maine, and Lafayette College in Easton, Pennsylvania. During his tenure at Colby College, he built and used a laser-based trap to study ultracold atoms.

Atoms can be in one of five states – solid, liquid, gas, plasma, and Bose-Einstein condensate. While the first four states are thoroughly researched, the fifth was observed only in the last decade of the 20th century.

Matter can enter the Bose-Einstein condensate state when atoms reach near absolute zero temperature, at a small fraction of one degree Kelvin. At this point atoms can barely move, having virtually no energy. That results in them bundling together and beginning to act collectively as a single particle.

Scientists use diffuse gas to create Bose-Einstein condensate, often rubidium. They use lasers to cool it down and drain the atoms of most of their energy. Finally, evaporative cooling — similar to how your cup of morning coffee cools off — trap takes away most of the atoms’ remaining kinetic energy.

The Basics of Raman Laser Spectroscopy

Based in Boulder, Colorado, Andrew Kortyna is an established researcher with a background spanning atomic, molecular, and optical physics. Andrew Kortyna’s current specialization is frequency metrology and high-precision laser spectroscopy.

In laser spectroscopy, a laser beam is directed at a physical sample. The sample can absorb or scatter the laser light. The characteristics of the absorbed and scattered light yield insight into the structure and dynamics of the sample. One approach among various techniques is Raman spectroscopy, which measures how monochromatic light scatters from a sample.

The process involves a high-intensity laser (such as an argon-ion laser or solid-state laser) being trained through a system of mirrors and lenses that focuses monochromatic light on the sample. While a majority of the light is either transmitted or scattered by the sample with no change in wavelength, a small portion interacts with the sample and scatters with shifted wavelengths.

The wavelength shift is caused by the interactions between the laser’s light and energy structure of sample. In solids, the light can interact with phonons, which are vibrations that occur naturally in many solids. These phonons behave very much like particles. Energy can be transferred between the vibrations and the laser light, causing the laser beam photons to gaining or losing energy from the phonons. This energy shift causes a change of wavelength that provides information about the system’s phonon modes, as well as the specific molecules structure found within the sample. There are a wide range of techniques that build on this fundamental spectroscopy phenomenon.