Intramolecular nuclear and electronic dynamics

Plane-polarised radiation is obtained when the phase factor a is equal to 0 or n and E = E. When a = 0, Ex and Ez are in phase, whilst for a = n they are out-of-phase by n. The special case illustrated in figure 1.2 corresponds to E = 0. Other forms of polarisation can be obtained from equations (1.6). For elliptically-polarised radiation we set a = n/2 so that equations (1.6) become 

If Ex = Ez = for a = n/2, we have circularly-polarised radiation given by the expression 

When viewed looking back along the Y axis towards the radiation source, the field rotates clockwise or counter clockwise about the Y axis. When a = +n/2 which corresponds to E, the field appears to rotate counter clockwise about Y. 

Conventional sources of electromagnetic radiation are incoherent, which means that the waves associated with any two photons of the same wavelength are, in general, out-of-phase and have a random phase relation with each other. Laser radiation, however, has both spatial and temporal coherence, which gives it special importance for many applications. 

In order to understand molecular energy levels, it is helpftd to partition the kinetic energies of the nuclei and electrons in a molecule into parts which, if possible, separately represent the electronic, vibrational and rotational motions of the molecule. The details of the processes by which this partitioning is achieved are presented in chapter 2. Here we give a summary of the main procedures and results. 

Here y = 27Tv, y is the angular frequency in units of rad s, v is the frequency in Hz, and is called the propagation vector with units of inverse length. In a vacuum k has a magnitude equal to 27t/Xo where Xq is the vacuum wavelength of the radiation. Finally, a is the difference in phase between the X and Z components of .  

---

Wigner rotation/adiabatic-to-diabatic transformation matrices, 92 Electronic structure theory, electron nuclear dynamics (END) structure and properties, 326-327 theoretical background, 324-325 time-dependent variational principle (TDVP), general nuclear dynamics, 334-337 Electronic wave function, permutational symmetry, 680-682 Electron nuclear dynamics (END) degenerate states chemistry, xii-xiii direct molecular dynamics, structure and properties, 327 molecular systems, 337-351 final-state analysis, 342-349 intramolecular electron transfer,... 

---