Related Experiment Video
Updated: Jul 17, 2026
08:52
Near-Infrared Temperature Measurement Technique for Water Surrounding an Induction-heated Small Magnetic Sphere
Published on: April 30, 2018
Water on the sun: line assignments based on variational calculations
O L Polyansky1, N F Zobov, S Viti
1Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK.
Science (New York, N.Y.)
|July 18, 1997
Summary
Researchers assigned the infrared spectrum of hot water in a sunspot. Variational solutions, not perturbation theory, were key to understanding the complex spectrum and its unexpected features at high temperatures.
Area of Science:
- Astronomy
- Astrophysics
- Spectroscopy
- Quantum Chemistry
Background:
- Sunspots provide extreme conditions (3200 K) for observing molecular spectra.
- Hot water molecules in sunspots exhibit complex infrared spectra.
- Traditional spectroscopic methods struggle with highly congested spectra.
Purpose of the Study:
- To assign the pure rotational infrared spectrum of water in a sunspot.
- To investigate the limitations of perturbation theory for hot molecules.
- To explore advanced computational methods for spectral analysis.
Main Methods:
- Utilized accurate variational solutions of the vibration-rotation Schrödinger equation.
- Analyzed the 10-micrometer infrared spectrum of water.
- Calculated energy levels up to half the dissociation limit.
Main Results:
- Successfully assigned the complex infrared spectrum of hot water.
- Observed unexpected spectral features, including rotational difference bands.
- Found fewer degeneracies than predicted by traditional theories.
- Demonstrated the inadequacy of perturbation theory for this system.
Conclusions:
- First principles calculations are essential for assigning spectra of hot polyatomic molecules.
- Variational methods provide accurate solutions for complex molecular spectra under extreme conditions.
- This study advances our understanding of molecular behavior in astrophysical environments.
More Related Videos
Related Concept Videos
01:16UV–Vis Spectroscopy: Molecular Electronic Transitions
In Ultraviolet–Visible (UV–Vis) spectroscopy, the absorption of electromagnetic radiation is used to probe the electronic structure of molecules. This technique provides insights into molecular electronic transitions, particularly the movement of electrons between different molecular orbitals. Radiation is absorbed if the energy of the electromagnetic radiation passing through the molecule is precisely equal to the energy difference between the excited and ground states. During this process,...
01:29Equipotential Surfaces and Field Lines
Electric potential can be pictorially represented as a three-dimensional surface. On such a surface, the electric potential is constant everywhere. The equipotential surface is always perpendicular to the electric field lines, and while it is three-dimensional, it can be treated as an equipotential line in a two-dimensional case. These equipotential lines are also always perpendicular to electric field lines. The term equipotential is often used as a noun, referring to an equipotential line or...
01:28Magnetostatic Boundary Conditions
An electric field suffers a discontinuity at a surface charge. Similarly, a magnetic field is discontinuous at a surface current. The perpendicular component of a magnetic field is continuous across the interface of two magnetic mediums. In contrast, its parallel component, perpendicular to the current, is discontinuous by the amount equal to the product of the vacuum permeability and the surface current. Like the scalar potential in electrostatics, the vector potential is also continuous...
01:17Chemical Shift: Internal References and Solvent Effects
In an NMR sample, precise measurement of the absolute absorption frequencies of nuclei is difficult. A standard internal reference compound is added, and the frequency difference between the reference signal and sample signals is measured.
The internal reference compound generally used in NMR spectroscopy is tetramethylsilane (TMS). TMS is preferred because it is chemically inert, soluble in NMR solvents, and easily removable. Also, the highly shielded methyl protons in TMS yield an intense...
The internal reference compound generally used in NMR spectroscopy is tetramethylsilane (TMS). TMS is preferred because it is chemically inert, soluble in NMR solvents, and easily removable. Also, the highly shielded methyl protons in TMS yield an intense...
01:21Boundary Conditions: Lossless Lines
Consider a single-phase, two-wire, lossless transmission line terminated by an impedance at the receiving end and a source with Thevenin voltage and impedance at the sending end. The line, with length, has a surge impedance and wave velocity determined by the line's inductance and capacitance.
At the receiving end, the boundary condition states that the voltage equals the product of the receiving-end impedance and current. This relationship is expressed as a function of the incident and...
At the receiving end, the boundary condition states that the voltage equals the product of the receiving-end impedance and current. This relationship is expressed as a function of the incident and...
01:27Energy Line and Hydraulic Gradient Line
Based on Bernoulli's equation, the energy line (EL) and hydraulic grade line (HGL) provide graphical representations of energy distribution in a fluid flow system. For steady, incompressible, inviscid flows, Bernoulli's equation is expressed as: