(1) Bond dissociation, formation, and relaxation and the valence electron and
surface potential barrier evolution are involved simultaneously upon chemical
reactions. O 2 dissociates into 2O atoms that bond to one Cu atom in the top
layer to form a pair of off-centered pyramids, [O
− Cu
2+ O
− ].
(2) Each of the O
− bonds to a Cu atom underneath to form the second Cu–O bond
is associated with bond angle and length relaxation. The O
2− ionic polarization
squeezes every fourth row of Cu atoms to evaporate from the (√2Â2√2)R45°
surface, leading to the ordered missing-row vacancies.
(3) The sp
3 orbital hybridization takes place subsequently, and the nonbonding
electron lone pairs polarize its Cu neighbours into paired dipoles across the
missing-row vacancies.
(4) Further bond relaxation stabilizes the surface and turns the ∠Cu–O–Cu angle
from 90° to 105° and the ∠Cu:O:Cu from 130° to 150° with “:” being the lone
pair on oxygen, which expands the first layer spacing from 0.185 to 0.194 nm.
It ascertains that an O atom tends to form a tetrahedral structure in the solid
phase and that one O cannot form two or more bonds with a specific host atom
because of the bond geometry restriction. The bond formation dynamics are subject
to the host lattice constant, geometry, and electronegativity. VLEED forms such a
uniquely sophisticated means that integrates information on the bond-barrier-band
energetics and dynamics which holds general for the oxidation of diamond and
other metallic surfaces, and N and C absorption as well.
Part III is focused on the Raman and infrared phonon spectrometrics for information about bond length and bond energy under multifield perturbation. The
BOLS-LBA derived DPS resolves the transition of abundance-stiffness-fluctuation
of oscillating bonds upon perturbation or reaction. Exercises have quantified the
local bond length and energy relaxation of group IV, III–V, II–VI nanocrystals,
layered graphene ribbons and WX 2 flakes, and the hydrogen bond network of water
ice and aqueous solutions. Practice has revealed the following:
(1) Molecular undercoordination-induced phonon frequency shift specifies the
reference from which the phonon frequency shifts, bond nature index, as well as
the manner and bond number in the specific mode of vibration. Atomic dimer
vibration governs and stiffens the translational optical G mode of graphene, and
the E g mode of black phosphor, TiO 2 , and WX 2 , while the collective vibration
of an atom with its nearest neighbours softens the longitudinal optical D modes
of graphene, A g mode of WX 2 , and TiO 2 upon crystal size reduction.
(2) Pressure stiffened phonon frequency and elasticity enable the derivation of the
binding energy density and the elasticity of a crystal, which is beyond the
Grüneisen description. The uniaxial strain-induced phonon relaxation and
phonon band splitting enable the derivation of the single-bond force constant
and the relative direction between a specific bond and the applied strain in
graphene and MoS 2 .
(3) Temperature-dependent phonon relaxation, band gap, and elasticity follow the
same Debye thermal decay, which gives rise to the atomic cohesive energy and
the Debye temperature of a substance of interest.
xii
Preface
surface potential barrier evolution are involved simultaneously upon chemical
reactions. O 2 dissociates into 2O atoms that bond to one Cu atom in the top
layer to form a pair of off-centered pyramids, [O
− Cu
2+ O
− ].
(2) Each of the O
− bonds to a Cu atom underneath to form the second Cu–O bond
is associated with bond angle and length relaxation. The O
2− ionic polarization
squeezes every fourth row of Cu atoms to evaporate from the (√2Â2√2)R45°
surface, leading to the ordered missing-row vacancies.
(3) The sp
3 orbital hybridization takes place subsequently, and the nonbonding
electron lone pairs polarize its Cu neighbours into paired dipoles across the
missing-row vacancies.
(4) Further bond relaxation stabilizes the surface and turns the ∠Cu–O–Cu angle
from 90° to 105° and the ∠Cu:O:Cu from 130° to 150° with “:” being the lone
pair on oxygen, which expands the first layer spacing from 0.185 to 0.194 nm.
It ascertains that an O atom tends to form a tetrahedral structure in the solid
phase and that one O cannot form two or more bonds with a specific host atom
because of the bond geometry restriction. The bond formation dynamics are subject
to the host lattice constant, geometry, and electronegativity. VLEED forms such a
uniquely sophisticated means that integrates information on the bond-barrier-band
energetics and dynamics which holds general for the oxidation of diamond and
other metallic surfaces, and N and C absorption as well.
Part III is focused on the Raman and infrared phonon spectrometrics for information about bond length and bond energy under multifield perturbation. The
BOLS-LBA derived DPS resolves the transition of abundance-stiffness-fluctuation
of oscillating bonds upon perturbation or reaction. Exercises have quantified the
local bond length and energy relaxation of group IV, III–V, II–VI nanocrystals,
layered graphene ribbons and WX 2 flakes, and the hydrogen bond network of water
ice and aqueous solutions. Practice has revealed the following:
(1) Molecular undercoordination-induced phonon frequency shift specifies the
reference from which the phonon frequency shifts, bond nature index, as well as
the manner and bond number in the specific mode of vibration. Atomic dimer
vibration governs and stiffens the translational optical G mode of graphene, and
the E g mode of black phosphor, TiO 2 , and WX 2 , while the collective vibration
of an atom with its nearest neighbours softens the longitudinal optical D modes
of graphene, A g mode of WX 2 , and TiO 2 upon crystal size reduction.
(2) Pressure stiffened phonon frequency and elasticity enable the derivation of the
binding energy density and the elasticity of a crystal, which is beyond the
Grüneisen description. The uniaxial strain-induced phonon relaxation and
phonon band splitting enable the derivation of the single-bond force constant
and the relative direction between a specific bond and the applied strain in
graphene and MoS 2 .
(3) Temperature-dependent phonon relaxation, band gap, and elasticity follow the
same Debye thermal decay, which gives rise to the atomic cohesive energy and
the Debye temperature of a substance of interest.
xii
Preface