21.4 Formulation of Multifield Perturbation
409
constant κ 0 . The λ characterizes the actual strain of the orientated bonds in a basic
unit from the complex of multiple bonds in different orientations. The strain can be
along (λ = 1) or perpendicular (λ = 0) or random (0 < λ < 1) to a certain bond
in the specimen. The bond along the strain is subject to a maximal extension and
its phonon frequency shifts most; the bond perpendicular to the strain is subject to
zero extension and keeps its phonon frequency. It is therefore not surprising that the
mechanical strain splits the phonon band and the extent of splitting depends on the
angle between the bond and the strain [16].
21.5 From Spectroscopy to Spectrometrics
A phonon spectral peak, probed either from Raman scattering or infrared absorption,
called a vibration mode or a phonon band, features the Fourier transformation of all
bonds vibrating in the similar frequency, irrespective of their locations or orientations
in the real space of the solid, liquid, or the vapor phase of a substance in characteristic peaks. Fourier transformation gathers the vibration modes according to the bond
stiffness and population in terms of the intrinsic vibrating dimers’ force constants,
or curvatures of the resultant potentials acting on the vibrating dimer at equilibrium.
Multifield activation, electron entrapment and polarization, and light radiation contribute to the crystal potentials whose curvatures determine intrinsically the lattice
oscillation dynamics.
Amplifying the phonon spectroscopy to spectrometrics aims to capturing the
conventionally-unexpected information on the bonding dynamics by avoiding spectral peak decomposition or empirical simulation using hypothetic models. Compared
with the electron spectrometrics that applies to conductive or semiconductive substance under high vacuum, the phonon spectrometrics extends to liquids and insulating species under multifield perturbation. The phonon spectrometrics directly captures bond relaxation information but the electron spectrometrics captures the effect
of bond relaxation on the electronic dynamics in various energy levels or bands [7].
When an external perturbation is applied, the interatomic potential will change,
and the characteristic phonon frequency will evolve or transit from its first state to a
new one in terms of abundance, stiffness, and fluctuation order, which gives profound
information on the bond relaxation that triggers the electronic structure and properties of the substance. External perturbations include atomic irregular-coordination,
mechanical activation, thermal excitation, charge injection by doping and aqueous
solvation, electrification and magnification, radiation, etc. Correlating the phonon
relaxation to the applied perturbation yields the ever-unexpected information.
Besides direct calculation of the ω(x) to match the measured frequency shift of a
substance under x perturbation, the other convenient method is to find the fraction of
abundance transition and frequency shift using the differential phonon spectrometrics (DPS) strategy [58, 59]. The DPS purifies merely the transition in the phonon
abundance and bond stiffness by conditioning, which monitors the phonon relaxation
409
constant κ 0 . The λ characterizes the actual strain of the orientated bonds in a basic
unit from the complex of multiple bonds in different orientations. The strain can be
along (λ = 1) or perpendicular (λ = 0) or random (0 < λ < 1) to a certain bond
in the specimen. The bond along the strain is subject to a maximal extension and
its phonon frequency shifts most; the bond perpendicular to the strain is subject to
zero extension and keeps its phonon frequency. It is therefore not surprising that the
mechanical strain splits the phonon band and the extent of splitting depends on the
angle between the bond and the strain [16].
21.5 From Spectroscopy to Spectrometrics
A phonon spectral peak, probed either from Raman scattering or infrared absorption,
called a vibration mode or a phonon band, features the Fourier transformation of all
bonds vibrating in the similar frequency, irrespective of their locations or orientations
in the real space of the solid, liquid, or the vapor phase of a substance in characteristic peaks. Fourier transformation gathers the vibration modes according to the bond
stiffness and population in terms of the intrinsic vibrating dimers’ force constants,
or curvatures of the resultant potentials acting on the vibrating dimer at equilibrium.
Multifield activation, electron entrapment and polarization, and light radiation contribute to the crystal potentials whose curvatures determine intrinsically the lattice
oscillation dynamics.
Amplifying the phonon spectroscopy to spectrometrics aims to capturing the
conventionally-unexpected information on the bonding dynamics by avoiding spectral peak decomposition or empirical simulation using hypothetic models. Compared
with the electron spectrometrics that applies to conductive or semiconductive substance under high vacuum, the phonon spectrometrics extends to liquids and insulating species under multifield perturbation. The phonon spectrometrics directly captures bond relaxation information but the electron spectrometrics captures the effect
of bond relaxation on the electronic dynamics in various energy levels or bands [7].
When an external perturbation is applied, the interatomic potential will change,
and the characteristic phonon frequency will evolve or transit from its first state to a
new one in terms of abundance, stiffness, and fluctuation order, which gives profound
information on the bond relaxation that triggers the electronic structure and properties of the substance. External perturbations include atomic irregular-coordination,
mechanical activation, thermal excitation, charge injection by doping and aqueous
solvation, electrification and magnification, radiation, etc. Correlating the phonon
relaxation to the applied perturbation yields the ever-unexpected information.
Besides direct calculation of the ω(x) to match the measured frequency shift of a
substance under x perturbation, the other convenient method is to find the fraction of
abundance transition and frequency shift using the differential phonon spectrometrics (DPS) strategy [58, 59]. The DPS purifies merely the transition in the phonon
abundance and bond stiffness by conditioning, which monitors the phonon relaxation