THz spectroscopy could help explain water's anomalies

THz spectroscopy could help Explain water's anomalies
Dipolar Lennard-Jones sphere solvated in water. Credit: Hamm

Liquid water sustains life on earth, but its physical properties remain mysterious among scientific researchers. Recently, a team of Swiss researchers used existing THz spectroscopy techniques to measure liquid water's hydrogen bonding. Future efforts with this technique could one day help explain water's peculiar properties. The team reports their findings in The Journal of Chemical Physics.

"What makes this paper special is the aspect of THz spectroscopy of a liquid. In the THz range, we make spectroscopy explicitly of the intermolecular degrees of freedom of the system in the study, to contrast it to intramolecular degrees of freedom," said Peter Hamm, an author on the paper. "With THz spectroscopy, we can very directly look at the hydrogen bonding between various ."

Researchers use spectroscopy to measure the interaction of matter with light and infer something's physical composition. In this experiment, the excited a dye molecule dissolved in water with an ultrashort visible laser pulse, changing its charge distribution. Then, a THz pulse measured the response of the surrounding water molecules as a function of the time after that excitation process.

THz spectroscopy, which is relatively low frequency, enables researchers to examine the forces that exist between water molecules. Observing these intermolecular forces could help researchers understand water's anomalies, because hydrogen bonding in molecules make up many of water's unexpected properties, like its unusual density maximum at 4 degrees Celsius.

"The response we found in the THz frequency range was surprisingly slow. Water is typically considered to be a very fast solvent with a response in the subpicosecond range, but we found a timescale around 10 picoseconds in the THz," Hamm said. They attributed the slow timescale to the collective nature of the water response that was probed using THz spectroscopy.

Hamm clarified that researchers have been using THz for more than 20 years and cautioned optimism about the results. "The outcome often has been a bit disappointing because the THz spectra of liquids like water are extremely broad and blurred, and it's very hard to extract information out of that," he said. Time-resolved techniques, like in this study, might overcome that limitation.

Next, the researchers plan to use their method to look at water's structure and dynamics when it's still liquid, but below the freezing point. Hamm explained, "The special properties of become significantly more pronounced if one goes to temperatures below the freezing point."


Explore further

X-ray laser reveals ultrafast dance of liquid water

More information: Saima Ahmed et al, Aqueous solvation from the water perspective, The Journal of Chemical Physics (2018). DOI: 10.1063/1.5034225
Journal information: Journal of Chemical Physics

Citation: THz spectroscopy could help explain water's anomalies (2018, June 27) retrieved 20 April 2019 from https://phys.org/news/2018-06-thz-spectroscopy-anomalies.html
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Jun 28, 2018
Actually there are no anomalies of H2O. There is just bad theory which is saddled with bad assumptions that are paradigmatically taboo for researchers. So speculative comments referring to "degrees of freedom" are just the tactics that the paradigmatically faithful employ to avoid confronting the fact that their theory sucks.

When you get the theory correct all of H2O's anomalies disappear:

The problem started with an omission by Linus Pauling:
Pauling's Omission: The Original Sin of the Natural Sciences
https://www.youtu...;t=1636s

Are You Confused About Hydrogen Bonding In Water?
https://youtu.be/RfNuWJDJvRw

James McGinn / Solving Tornadoes

Jun 30, 2018
" . . . the THz spectra of liquids like water are extremely broad and blurred, and it's very hard to extract information out of that," he said

The reasons for this "broad and blurred" spectra are explained in Pauling's Omission, linked above

Jun 30, 2018
If you want to advertise your book on physorg pay for the advertisement.

Jun 30, 2018
Meanwhile, all I see is water woo. Water woo is the most popular woo. https://rationalw...ater_woo

Next water woo up: homeopathy. After that: "structured water" (which is suspiciously close to what we're seeing here from @jimmagoo).

Jun 30, 2018
This comment has been removed by a moderator.

Jun 30, 2018
This comment has been removed by a moderator.

Jun 30, 2018
If you want to advertise your book on physorg pay for the advertisement.


You are a dull-witted moron who has nothing of substance to add to the issue. Find another hobby. Science involves thinking. Thinking is not something morons are good at.

Jun 30, 2018
Meanwhile, all I see is water woo. Water woo is the most popular woo. https://rationalw...ater_woo

Next water woo up: homeopathy. After that: "structured water" (which is suspiciously close to what we're seeing here from @jimmagoo).


LOL. You are so desperate that your only argument is to compare my well considered thinking to pseudo science. You don't have a real argument. You are a worthless POS.

Jun 30, 2018
ZoeBell:
THz spectroscopy could help explain water's anomalies These effects are easily understandable even without some spectra.

You will never provide any support for this statement.

ZoeBell:
Water molecules are curved and they don't pack together well.

There is a lot more to it than you suggest here. By all appearances, H2O molecules (at the molecular level) appear to defy Coulomb's law. (See link below for more details)

The mistake is that science has always assumed that the polar force is constant. It's not. It's variable. Understanding how and why it is actually variable is the key to understanding all of the anomalies of H2O:

The problem started with an omission by Linus Pauling:
Pauling's Omission: The Original Sin of the Natural Sciences
https://youtu.be/iIQSubWJeNg

James McGinn / Solving Tornadoes


Jun 30, 2018
shady links for shady 'science' I guess...

down voting can't help that.

Jun 30, 2018
There's no woo like water woo. Good luck with that sport.

Jul 01, 2018
You are a dull-witted moron who has nothing of substance to add to the issue. Find another hobby. Science involves thinking. Thinking is not something morons are good at.


You have a such wonderful sense of humor, your comments make me laugh. You should really comment more Claudius.

Jul 01, 2018
This comment has been removed by a moderator.

Jul 01, 2018
ZB:
I explained it bellow my sentence and I provided the links,

JMcG:
Read the title of the article, you worthless troll. Yes, water tends to cluster. So what? The article is referring to unresolved anomalies. My hypothesis addresses that issue.

I have no interest in debating your imagination.

Jul 01, 2018
There's no woo like water woo. Good luck with that sport.


Are the anomalies "woo" you frikin retard?

Jul 01, 2018
shady links for shady 'science' I guess...

down voting can't help that.


Uh, did you know that voting is not a scientific method?

Jul 02, 2018
jimmcginn wrote:


JMcG:
Read the title of the article, you worthless troll. Yes, water tends to cluster. So what? The article is referring to unresolved anomalies. My hypothesis addresses that issue.

I have no interest in debating your imagination.


Calling yourself a useless troll, fitting perhaps but I think I have a cure for arguing with yourself.. tincture of tap water, $100 and it's yours.

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