Researchers have investigated for the first time how two different forms of vanduo (ortho- and para-) behave differently when undergoing chemical reactions.
Vanduo is a chemical entity, a molecule in which a single deguonis atom is linked to two hydrogen atoms (H2O). Vanduo exists as liquid, solid (ice) and gas (vapours). It is among the few chemicals which do not contain anglis and still can be liquid at room temperature (about 20 degrees). Vanduo is ubiquitous and important for life. At the molecular level it is well known that everyday vanduo exists in two different forms but this information is not of common knowledge. These two forms of vanduo are called isomers and are referred to as ortho- or para- vanduo. The main difference between these forms is very subtle and is simply the relative orientation of the nuclear spins of the two hydrogen atoms which are aligned in either same or opposite direction, hence their names. This spin of hydrogen atoms is due to atomic physics though this phenomenon is not yet fully understood. These two forms have identical physical properties and it has been believed so far that they should also then have identical chemical properties.
Neseniai paskelbtame tyrime Gamta Communications, researchers from the University of Basel, Hamburg have for the first time investigated the difference in chemical reactivity of these two forms of vanduo and have proven that ortho- and para- forms react very differently. Chemical reactivity means the way or the ability by which a molecule undergoes a chemical reaction. The study involved separation of vanduo into its two isomeric forms (ortho- and para-) using an electrostatic deflector by involving electric fields. Since both these isomers are practically the same and have identical physical properties, this separation process is complex and challenging. The separation was achieved by this group of researchers by using a method based of electric fields developed by them for Free-Electron Laser Science. The deflector introduces an electric field to a beam of atomized water. Since there is crucial difference in nuclear spin in the two isomers, this slightly impacts the way by which atoms interact with this electric field. Therefore, as the water travels through the deflector it starts separating into its two forms ortho- and para-.
Researchers have demonstrated that para- vanduo reacts around 25 percent faster than ortho-water and its able to attract to a reakcija stipresnis partneris. Tai neabejotinai paaiškinama branduolio sukimosi skirtumu, kuris turi įtakos vandens molekulių sukimuisi. Be to, paravandens elektrinis laukas gali greičiau pritraukti jonus. Grupė toliau atliko kompiuterinį vandens molekulių modeliavimą, kad patvirtintų savo išvadas. Visi eksperimentai buvo atlikti su molekulėmis labai žemoje temperatūroje, beveik -273 laipsnių Celsijaus. Tai yra svarbus veiksnys, kaip paaiškino autoriai, kad tik tokiomis sąlygomis atskiros molekulių kvantinės būsenos ir energijos kiekis gali būti gerai apibrėžti ir geriau kontroliuojami. Tai reiškia, kad vandens molekulė stabilizuojasi kaip viena iš dviejų formų ir jų skirtumai tampa akivaizdūs ir aiškūs. Taigi cheminių reakcijų tyrimas gali atskleisti pagrindinius mechanizmus ir dinamiką, leidžiančią geriau suprasti. Tačiau praktinis šio tyrimo panaudojimas šiuo metu gali būti nelabai didelis.
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Šaltiniai)
Kilaj A et al 2018. Skirtingo para ir orto-vandens reaktyvumo į sulaikytus diazenilio jonus stebėjimas. Gamta Pranešimai. 9 straipsnio 1 dalį. https://doi.org/10.1038/s41467-018-04483-3
