Area under the following curve (Lorentzian type)

In summary, the area under a Lorentzian curve is a measure of the total intensity or signal of a physical phenomenon, and is calculated using the formula A = π * h * w or numerical integration methods. Factors such as peak height and width, background signal, and instrumental noise can affect the area. It may also be used to determine the concentration of a substance, but other factors can affect this relationship. However, it is not a reliable method for determining substance purity, and other methods may be more suitable.
  • #1
Rajini
621
4
Hello all,
I need to know the area under the following curve (Lorentzian type):
[tex]f(x)=\frac{I(\Gamma/2) ^2}{(x-x_0)+(\Gamma/2) ^2}=\frac{I\Gamma ^2}{4(x-x_0)+\Gamma ^2}[/tex].
In the above Loretzian function we all know that [tex]\Gamma[/tex] is fullwidth at half maximum, [tex]x_0[/tex] is peak's centre and [tex]I[/tex] is the height.
What is the area under Lorentzian function shown above (for [tex]x_0=0[/tex])?
[tex]\int f(x)=?[/tex].
please help me!
thanks
 
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  • #2


[tex]\int \frac {k}{b(x-a) + c}\, dx = \frac {k \ln(bx - ba + c)}{b} +C[/tex]
 
  • #3


Hello Kurtz,
thanks for your help!..

bye
 

1. What is the significance of the area under a Lorentzian curve?

The area under a Lorentzian curve represents the total intensity or signal of a physical phenomenon, such as an absorption or emission line in spectroscopy. It is a measure of the strength or concentration of the phenomenon being observed.

2. How is the area under a Lorentzian curve calculated?

The area under a Lorentzian curve can be calculated using the formula A = π * h * w, where A is the area, h is the height of the peak, and w is the full width at half maximum (FWHM) of the curve. Alternatively, it can be calculated using numerical integration methods.

3. What factors affect the area under a Lorentzian curve?

The area under a Lorentzian curve is affected by the height and width of the peak, as well as the baseline or background signal. It can also be affected by factors such as instrumental noise, overlap with other peaks, and the resolution of the measurement instrument.

4. What is the relationship between the area under a Lorentzian curve and the concentration of a substance?

In some cases, the area under a Lorentzian curve can be directly proportional to the concentration of a substance being measured. However, this relationship may be affected by other factors such as the sensitivity of the measurement method and the presence of interferences.

5. Can the area under a Lorentzian curve be used to determine the purity of a substance?

The area under a Lorentzian curve is not a reliable method for determining the purity of a substance. This is because the area is affected by multiple factors, and a small change in any of these factors can result in a significant change in the calculated area. Other methods, such as peak area ratios or peak height ratios, may be more suitable for determining substance purity.

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