Hey there Kamal Mustafa!

When it comes to calculating the absorption coefficient (alpha) for perovskite oxide materials to determine the band gap, it's crucial to use the right formula for accurate results. Here's a breakdown of the formulas you've Kamal Mustafa mentioned:

1. alpha = 4 * 3.14 * A / lambda

2. alpha = 2.303 / A * 10^-7

3. alpha = 2.303 * A

4. alpha = A * 1000 * density / (l * c * M)

Each formula serves a different purpose and might be applicable under specific conditions. Let's evaluate them:

1. The first formula seems to be based on the relationship between absorption coefficient, absorption cross-section (A), and wavelength (lambda). It's commonly used in spectroscopy and optics.

2. The second formula appears to be derived from the Beer-Lambert law, which relates absorbance, molar absorptivity (A), path length (l), and concentration (C). However, it doesn't seem directly related to absorption coefficient for band gap calculation.

3. The third formula seems to be a simplified version of the Beer-Lambert law, but again, it doesn't directly address band gap calculation.

4. The fourth formula integrates concentration, density, path length, and molar ratio, which could be more suitable for specific experimental setups where these parameters are relevant.

To determine which formula is correct for your Kamal Mustafa material and band gap calculation, consider the properties of your Kamal Mustafa perovskite oxide, the experimental setup, and the specific parameters you Kamal Mustafa need to measure. Additionally, consult literature or experts in your field to ensure the most accurate approach.

Remember, choosing the right formula is key to obtaining reliable results in your research. If you Kamal Mustafa have any further questions or need clarification on any of the formulas, feel free to ask!

Thanku brother good answer with detail, i have to check the optical properties in my material. Should i use first one or the fourth one is better?

Kaushik shandilya if i use fourth formula then for C concentration (should i use all element concentration addition) for each sample having different elements?

For example for one sample ABX3 C=(concentration of A+ concentration of B)