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24 Water and Aqueous Solutions
24.1 Water and Aqueous Solutions
Water ice is ubiquitously important to agriculture, climate, environment, quality-oflife, and life sustainability. O:H dissociation for water harvesting and H–O bond
dissociation for H 2 generating are strategies to conquering resource crisis; hydration
and solvation laid foundations to ionic rejection in water desalination and protein
dissolution; aqueous drug-cell and water-protein interfaces are of great importance to
microbiology, disease curing, DNA regulating and signaling. Therefore, grasp with
factors dictating the performance of H 2 O molecules and their electrons is pivotal to
deep engineering the liquid water and controlling its reaction, transition, and transport
dynamics.
Water ice responds to perturbation such as compression, heating, electromagnetic
radiation, and molecular undercoordination irregularly leading to anomalies such
as ice friction, ice floating, ice regelation, supercooling/superheating, warm water
quick cooling, etc. Acid, base and salt solvation makes the solution even amazing.
The O:H–O bonds (or HB) in the hydration shells of solutes perform differently from
they do in the ordinary water.
Much effort has been focused on the motion manner and dynamics of the excessive hydrated charge (proton and line-pair) and molecules with debating mechanisms.
One often considers the solute motion dynamics in terms of phonon or molecular
lifetime in the hydrating states, drift diffusivity, by taking the H 2 O molecule as the
basic structural unit. It was unclear how the H
+ , HO
− , Y
+ , and X
− ions functionalize
collaboratively the hydration network and properties of the Lewis-Hofmeister solutions. Situations have been improved since the recent work focusing on the O:H–O
bond theory for the behavior of water ice [1], aqueous solutions [2], and energetic
cyclo-N 5
− molecular complexes [3].
The aim of this section is to show that a combination of the O:H–O bond cooperativity notion [4] and the DPS [5, 6] has enabled discoveries of O:H and H–
O phonon relaxation under the perturbations of heating, compression, molecular
undercoordination and charge injection by acid, base and salt solvation.
Figure 24.1 shows the full–frequency Raman spectra for the 0.1 malar ratio,
monovalent (a) HX acid [7], (b) YHO base [8], and (c) YX salt [9] solutions collected
under the ambient conditions and (d) heated water [10] (X = Cl, Br, I; Y = Li,
Na, K). The Raman spectrum covers the phonon bands of O:H stretching vibration
at <200 cm
−1 , the ∠O:H–O bending band centered at 400 cm
−1 , the ∠H–O–H
bending band at 1600 cm
−1 , and the H–O stretching band centered at 3200 cm
−1 .
The O:H stretching, molecular rotational and torsional vibrations are within the THz
regime, one can hardly discriminate these contributions one from the other. The
H–O stretching phonon band can be decomposed into the bulk (3200 cm
−1 ), the
skin or the surface having a certain thickness (3450 cm
−1 ), and the surface dangling
H–O bond or called free radical (3610 cm
−1 ) directing outwardly of the surface
[4]. Likewise, the O:H stretching vibration phonon centered at 75 cm
−1 features the
undercoordination–induced skin O:H elongation and polarization, the ~200 cm
−1
24 Water and Aqueous Solutions
24.1 Water and Aqueous Solutions
Water ice is ubiquitously important to agriculture, climate, environment, quality-oflife, and life sustainability. O:H dissociation for water harvesting and H–O bond
dissociation for H 2 generating are strategies to conquering resource crisis; hydration
and solvation laid foundations to ionic rejection in water desalination and protein
dissolution; aqueous drug-cell and water-protein interfaces are of great importance to
microbiology, disease curing, DNA regulating and signaling. Therefore, grasp with
factors dictating the performance of H 2 O molecules and their electrons is pivotal to
deep engineering the liquid water and controlling its reaction, transition, and transport
dynamics.
Water ice responds to perturbation such as compression, heating, electromagnetic
radiation, and molecular undercoordination irregularly leading to anomalies such
as ice friction, ice floating, ice regelation, supercooling/superheating, warm water
quick cooling, etc. Acid, base and salt solvation makes the solution even amazing.
The O:H–O bonds (or HB) in the hydration shells of solutes perform differently from
they do in the ordinary water.
Much effort has been focused on the motion manner and dynamics of the excessive hydrated charge (proton and line-pair) and molecules with debating mechanisms.
One often considers the solute motion dynamics in terms of phonon or molecular
lifetime in the hydrating states, drift diffusivity, by taking the H 2 O molecule as the
basic structural unit. It was unclear how the H
+ , HO
− , Y
+ , and X
− ions functionalize
collaboratively the hydration network and properties of the Lewis-Hofmeister solutions. Situations have been improved since the recent work focusing on the O:H–O
bond theory for the behavior of water ice [1], aqueous solutions [2], and energetic
cyclo-N 5
− molecular complexes [3].
The aim of this section is to show that a combination of the O:H–O bond cooperativity notion [4] and the DPS [5, 6] has enabled discoveries of O:H and H–
O phonon relaxation under the perturbations of heating, compression, molecular
undercoordination and charge injection by acid, base and salt solvation.
Figure 24.1 shows the full–frequency Raman spectra for the 0.1 malar ratio,
monovalent (a) HX acid [7], (b) YHO base [8], and (c) YX salt [9] solutions collected
under the ambient conditions and (d) heated water [10] (X = Cl, Br, I; Y = Li,
Na, K). The Raman spectrum covers the phonon bands of O:H stretching vibration
at <200 cm
−1 , the ∠O:H–O bending band centered at 400 cm
−1 , the ∠H–O–H
bending band at 1600 cm
−1 , and the H–O stretching band centered at 3200 cm
−1 .
The O:H stretching, molecular rotational and torsional vibrations are within the THz
regime, one can hardly discriminate these contributions one from the other. The
H–O stretching phonon band can be decomposed into the bulk (3200 cm
−1 ), the
skin or the surface having a certain thickness (3450 cm
−1 ), and the surface dangling
H–O bond or called free radical (3610 cm
−1 ) directing outwardly of the surface
[4]. Likewise, the O:H stretching vibration phonon centered at 75 cm
−1 features the
undercoordination–induced skin O:H elongation and polarization, the ~200 cm
−1