Here [V.sub.o] is the experimental equilibrium volume corresponding to experimental equilibrium

lattice constant ao= 12.754 a.u for RbBr.

The

lattice constant was calculated using the Nelson-Riley and Riley [9] relationships.

All the used materials have a cubic-type structure, but the

lattice constant for the Ta, [Y.sub.2][O.sub.3], Zr[O.sub.2], and TaC is 3.306, 10.604, 5,065, and 4.456 [Angstrom], respectively.

The variation of different crystallographic parameters viz.,

lattice constant, mean gain size, number of reflections per unit area, lattice strain, dislocation density, texture coefficient and standard deviation with different Zn concentration have been calculated from the experimentally observed XRD data and give in the Table-1.

The dimensions of the array and the CDR are illustrated in Figure 2, where identical CDR elements are arranged in square lattice structure with period (

lattice constant) that is assigned W letter.

The vacancy defects make

lattice constant change and band gap increase.

The "

lattice constant" represents the distance between the atoms.

As shown in Figure 2, the values of parameters were chosen as: [r.sub.1] = 0.165 * a, [r.sub.2] = 0, and [r.sub.3] = 0.054 * a, where a is the

lattice constant. The relationship between group velocity [V.sub.g] and wavenumbers k is shown in Eq.

In this case the

lattice constant of the quantum well material is almost matched with the

lattice constant of 5.8690 [Angstrom] of the barrier material.

In fact, AC structure can also be deemed as the quaternary layered periodic structure, with the

lattice constant of 2a and the materials arranged in ACAC sequence in each period.

The valence band offset for InBi is found out to be 0.35 eV from Figure 1 (drawn by using the data from [9]) corresponding to its

lattice constant of 6.686 [Angstrom] [12].

We consider 2D PhC waveguide as shown in Figure 1(a), consisting of a square lattice of GaAs rhombic cross-section elements in air background, having a

lattice constant of a = 815 nm.