Dear Dr. Tanzeeha.

The attached picture is the answer to: "What is the exact relationship between intensity and 2 theta in XRD"

Hi,

It may be possible that with increasing laser fluence, the PbO content may increase. Furthermore, texturing of a preferred plane depends of heating/cooling rates during laser ablation. The area under the peaks and FWHM are important  to estimate the amount of phase. Moreover, what is the particle size  estimated using Scherrer's equation? 

Dear Dr. Tanzeeha.

The attached picture is the answer to: "What is the exact relationship between intensity and 2 theta in XRD"

There are a few things to think about that may help you, in addition to previous thoughts. The intensities of diffraction maxima do depend on many variables but in your case I think one major contributor to variance would be atom occupancy. The reason I think that is because the oxidation behavior of Pb is very complex and very easily modified. You said you varied energy, I am assuming in the ablation pulse? This will change the oxidation characteristics of Pb/PbO, and therefore other phases are likely forming in your samples such as Pb2O3, Pb3O4, and others (including defective forms of the origional phases). On that note, the PbO, PbO2, and Pb3O4 that may be present will likely exist in both orthorhombic and tetragonal phases so you must be careful. I suggest also looking for monoclinic Pb2O3 as well if you have unassigned peaks.

So basically I am saying that the Pb oxidation behavior is very complex and by ablating I think you are probably seeing the formation of several, if not many, phases. In addition, the phases that exist may be very imperfect, having high variances in atom occupancy (O as well as Pb) so your diffraction maxima intensity will vary along with their positions. Look for new peaks coming up and try to refine them with current models to determine structure.

Hope that helps.

Alex  B. Cusak sir i think you have understood my problem more closely. I have also perform same experiment on Pure tin metal and got the same result....I dont know how to explain that variation in peaks intensity.

I have always thought that increases in the intensity of certain peak mean the quantitative increment (amount) of oxide or Pb. Same with tin and tin oxide

My EDX results shows decrease in oxide ration and increase in metal (Pb & Sn) ratio. My XRD results shows that the insity of Oxide peaks decreasing and metal increasing with the inclease of laser energy.... How come i relate these results?

Yes I agree it is usually the case that RELATIVE intensities between phases represents relative quantities, but like i said the occupancy (in other words degree of crystallinity) of each plays a large role. For example, if you see a single peak from one phase change intensity relative to the others from that phase that is not a quantity change but an occupancy change I think. If you see all intensities increase relative to all from another phase, than I would surmise that the quantity of that phase has increased relative to the other. Not sure if that's clear!

The amount of each phase is related to the area of XRD-related peaks. But not only  peaks with highest intensity. An average must be done.

XRD pattern must be corrected using data related to the effect of XRD-appartus (deduced by using a standard sample for XRD measurement)

Best reagards 

"My XRD results shows that the insity of Oxide peaks decreasing and metal increasing with the inclease of laser energy.... How come i relate these results?" u cant use single peak for quantify but a whole pattern by refinement, in this case Rietveld refinement.

Would you mind to attach ur XRD raw data?

Dear colleague Tanzeeha Jafari,

Have a nice time and good day.

If the material has much defects, localized states, imperfections, such this condition represented as a hump or halo  through the XRD chart with low XRD intensity. The material under investigation is amorphous and has no any identified structure phase, no order and consequently no presence of any peaks. (see the attached Fig.)

 If the material has less or no defects, localized states, imperfections, then the material will has some extent of order it depends on the density’ low or zero  density of defects, localized states, imperfections means the presence of order or arrangement, this represented by the presence of sharp peaks with different FWHM’s which means the presence of crystalline phases. The high XRD intensity indicated the high crystalline structure, if the peak has a small FWHM and/or high intensity this means high crystallite size, high order and arrangement. The intensity and the FWHM are function of preferred orientation. (see the attached Fig.).

I wish this is useful and help you.

Yours

A.   El-Denglawey

Dear Dr Tanzeeha

 The following is hint about the exact relationship between 2 theta and XRD intensity: 

1.   Ihkl ∝ |Fhkl|2

2.  Intensity and 2 theta exactly related by the scatter factor Fhkl , where this structure factor Fhkl sums the result of scattering from all of the atoms in the unit cell to form a diffraction peak from the (hkl) planes of atoms.

3.     You can get details from ppt. slides of Basics on X-ray powder diffraction, prepared by MIT, available in the net.

,  

Hi!

Plz find attached herewith a paper related to your question. Again, your are dealing with heat (Laser). so, crystallite size of the phases are drastically very, microstrain can be formed, hence the intensity changes, try to estimate those parameters.

My xrd results  ( tin and tin-oxide) of samples prepared in de-ionized water at four different energies (60, 120, 180, and 240 mJ)...I have attached two documents, Both are same results in different format.  Here * and # shows different oxides common planes and  rest are the tin peaks.

How can i analyze it

Why don't you normalize each profile w.r.t. its own integrated intensity and then superimpose them to compare in log scale :-)

You'll amaze yourself!

https://www.flickr.com/photos/85210325@N04/14348388500/in/album-72157645018820696/

Dear Dr. Tanzeeha. Do You have the original file? Regards

There is a beautiful description about XRD. i hope it will help you.

http://pd.chem.ucl.ac.uk/pdnn/pdindex.htm#diff1

Best Regards

A. Ahad

Dear Dr. Tanzeeha,

Would you please check the Thomson equation for a single electron? You will get your answer.

Please visit: https://www.embl-hamburg.de/biosaxs/courses/embo2010/slides/saxs-basics-vachette.pdf

(2) Please check also the XRD equation for a crystal. The other solution is that X-Ray Diffraction from crystal (Elements of X-ray Diffraction,2nd Ed., by B.D. Cullity, Addison-Wesley, 1978). For this please visit: http://www.chem.uci.edu/~lawm/263%204.pdf

Best regadrs,

Prof. Dr. MKH Bhuiyan

Please send me your XRD files and let me know what kind of analysis you want. You can also contact Dr. Zahida Malik in NUST to get some help.

Shortly speaking, first you have to compare your pattern with theoretical powder diffraction pattern and look for major peaks, meaning the five peaks with first five large structure factors. This is for phase identification, meaning first step to make sure what phases you have in your sample. 

Then, if the relative intensity between peaks changes, then it means there is preferred orientation of your measured sample, or say, preferred crystallographic planes are grown in your sample. 

Next, if your peak is broadened, use the Scherrer's equation to calculate the particle size, and compare your d-spacing derived by 2-theta angle with the theoretical ones. This can give you many information about the strain, defects in the sample.

Make sure your measurement is good, meaning that you should use zero background holder for measurement, and your system config should be right in order to minimize the  background.

Also, your XRD pattern should be labeled more clearly, I don't know which peak you are labeling.

Regarding EDX, in order to link that to the XRD result, you have to make sure your sample is homogeneous everywhere, meaning your EDX cannot simply represents some random local case.

Hope this helps. Thank you

Thanks to all specially to you Zhimini