Harmonics High frequency

Here, HFree is the Hamiltonian of the free harmonic high frequency oscillator and Hint is that giving the anharmonic interaction between the slow and fast modes, which are, respectively, given by... 

Ohihoff C, Lupke G, Meyer C and Kurz H 1997 Static and high-frequency electric fields in silicon MOS and MS structures probed by optical second-harmonic generation Phys. Rev. B 55 4596-606... 

For very-high-accuracy ah initio calculations, the harmonic oscillator approximation may be the largest source of error. The harmonic oscillator frequencies... 

Other than the system harmonics, electrical interferences are also caused by line disturbances, which may be caused by lightning, switching, sparking or a fault. As discussed in Chapter 17, line disturbances occur at very high frequencies but some may coincide with the audio frequency of telephone lines, and cause disturbance in the audio quality of the telephone system. All these disturbances are referred to as inductive interferences. 

Potential control rectifiers can also be constructed using thyristors. However, these produce strong high-frequency harmonic waves that can be transmitted to... 

Raman excitation. and I2s are the high-frequency and low-frequency components of the pump light pulse. A probe pulse of frequency 12 interacts with the coherence to present the optical response of the fundamental frequency 12 + C0fsl2. (c) Fourth-order coherent Raman scattering, the optical response of the second harmonic frequency 212 + co 2I2 is modulated by the vibrational coherence. 

The high-frequency mode is coupled through the anharmonicity coefficient y with the low-frequency mode which is a resonant one due to harmonic interaction with the surface reservoir. For simplicity, the last term is written in the Gaitler-London approximation (compare with more general Eq. (4.1.8) where this restriction is absent). The required GF of the high-frequency mode can be obtained from the... 

In the Heitler-London approximation, with allowance made only for biquadratic anharmonic coupling between collectivized high-frequency and low-frequency modes of a lattice of adsorbed molecules (admolecular lattice), the total Hamiltonian (4.3.1) can be written as a sum of harmonic and anharmonic contributions ... 

Some of lowest-order diagrams for the temperature GF (A3.6) are shown in Fig. A3.1. The dashed and the solid lines represent the GFs of high-frequency and low-frequency vibrations of a planar lattice in the harmonic approximation ... 

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