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Vibrational studies of advanced materials

Prachurya BharadwajCUJ/I/2010/INT/25

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Acknowledgement

I am grateful to my research guide Arnab Sankar Bhattacharyya, Phd for his constant encouragement and support throughout these past 9 months while I was working on this project.

My heartiest gratitude to every teacher who has ever contributed in my knowledge and skills in science, technology and their application in the modern world.

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Contents:

Compounds studied through literature review…………………..slide 3

Energies present inside a molecule……………………………….slide 4

Equations used in the computing the vibrational and dissociation energies………………………………………………..…………slide 5

Procedure implemented in this research…………………………..slide 6

Discussions …………………………………………………………….slide 13-24

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Few of the compounds reviewed from the published research papers:

PVC/PMMA blend based polymer electrolytesLigninDithienylethylene switchesLaPO4

Poly Ethylene Glycol.Silver-Poly(Methylmethacrylate)Epoxy Polyester Hybrid Coating System.SoilPVC Based Polymer Electrolyte SystemsPACLITAXEL DRUGS

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Energies present in the atomic level:1. Vibrational2. Rotational 3. Electronic

We are interested in Vibrational energies of diatomic molecules in this research work. Hence we shall be discussing about the vibrational energies of few common diatomic molecules and compare and contrast the graphs of each of these.

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Schrödinger’s equation is valid for diatomic molecules to describe the vibrational energy levels.v= 0, 1, 2,3…k= force constantµ= reduced massh= plank’s constant: 6.626 069 57 x 10-34 J s

This equation is used to find the vibrationl energies of 29 diatomic molecules

Real molecules do dissociate after a particular amount of energy is applied on it. This energy is dissociation energy and is shown as Deq in the equation on the left.

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Procedure implemented in this research:Step 1: creating a program to find out the vibrational energies of 29 diatomic molecules using the formula : The software used to create and run this program was Dev C++. Based on this program, we were able to find out the vibrational energies v/s deflections from equivalent position curves of 29 molecules. The curves and interpretation of these curves are discussed.

Step 2: creating an extension of the earlier program using the software Dev C++ to find out the dissociation energies of 29 molecules.

Step 3: Using the software Origin to plot the graphs of “vibrational energies v/s deflections from equivalent position” and “dissociation energies v/s deflections from equivalent positions” for 29 molecules. The graphs are shown in the results segment.

Step 4: Interpretation of these graphs to justify the slopes of vibrational energies and dissociation energies and relevant data (in Discussion segment).

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Force constants, bond lengths and masses of elements were found for 29 molecules taken into consideration in this research.

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The inputs from the previous slides were used in this program to find the vibrational energies of 29 molecules and then the dissociation energies.

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Henceforth they are exported to excel sheet and then the graphs pertaining to dissociation energy v/s deflections and vibrational energy v/s deflections are made in origin.

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Results found:There are several interesting results derived from this computational approach of finding out the vibrational energies and dissociation energies of 29 molecules:A list of 29 molecules with their respective vibrational energies, deflections from the equivalent positions and dissociation energies are drawn about.

{i} Vibrational energies of all the molecules, taken into consideration, show a gradual increase in magnitude with increase in distance from equivalent position.{ii} Vibrational energies correspond to the change in bond length that the molecule [linear diatomic molecule] goes through. As the atoms go farther from each other, even by degree of smallest of nanometers, the vibrational energy advances.{iii} The dissociation energy v/s deflections from equivalent positions graphs are found to be distinctively different from each other.

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Aluminum compounds : The vibrational bond energies of Aluminum compounds in this research are found in the order given as: AlN > AlP > AlAs > AlSb.The dissociation energies also show the same order: AlN > AlP > AlAs > AlSbThe force constants that correspond to the bond in diatomic molecules show , the following order for Aluminum compounds are as : AlN [15.93] > AlP [8.82] > AlAs [7.97] > AlSb [6.22]

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The vibrational bond energies of Boron compounds in this research are found in the order given as: BN > BFThe dissociation energies also show the same order: BN >BFThe force constants that correspond to the bond in diatomic molecules show , the following order for Boron compounds are as : BN[17.99] > BF[14.35]

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Cadmium compounds : The vibrational bond energies of Cadmium compounds in this research are found in the order given as: CdS > CdSe > CdTeThe dissociation energies also show the same order: CdS > CdSe > CdTeThe force constants that correspond to the bond in diatomic molecules show , the following order for Cadmium compounds are as : CdS[3.54] > CdSe[3.16] > CdTe[2.74]

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Zinc compounds : The vibrational bond energies of Zinc compounds in this research are found in the order given as: ZnS > ZnSe > ZnTeThe dissociation energies also show the same order: ZnS > ZnSe > ZnTeThe force constants that correspond to the bond in diatomic molecules show , the following order for Zinc compounds are : ZnS[4.42] > ZnSe[3.96] > ZnTe[3.48]

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Gallium compounds : : The vibrational bond energies of Gallium compounds in this research are found in the order given as: GaAs > GaSbThe dissociation energies also show the same order: GaAs > GaSb The force constants that correspond to the bond in diatomic molecules show , the following order for Gallium compounds are as : GaAs[7.61] > GaSb[5.95]

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Mercury compounds : The vibrational bond energies of Mercury compounds in this research are found in the order given as: HgSe > HgTe The dissociation energies also show the same order: HgSe > HgTe The force constants that correspond to the bond in diatomic molecules show , the following order for Mercury compounds are : HgSe[3.23] > HgTe[2.56]

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Indium compounds : The vibrational bond energies of Indium compounds in this research are found in the order given as: InP > InAs > InSbThe dissociation energies also show the same order: InP > InAs > InSbThe force constants that correspond to the bond in diatomic molecules show, the following order for Indium compounds are : InP[7.09] > InAs[6.51] > InSb[5.44]

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Hydrogen halides: The vibrational bond energies of hydrogen halide compounds in this research are found in the order given as: HF>HCl>HI>HBrThe dissociation energies show a similar order: HF>HCl>HI>HBrThe force constants that correspond to the bond in diatomic molecules show, the following order for hydrogen halides : HF[970]>HCl[482]>HBr[410]>HI[320] HBr has lesser vibrational energy and needs lesser dissociation energy than HI to break the bond but it has more force constant than HI. This proves that force constant is not the only deciding factor for the amount of energy required to dissociate a molecule. But based on the other molecules, we can say that it sure is one of the factors that lead to the amount of energy required to break the bond

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A interpretation of all the graphs bring us to this conclusion that the more amount of vibrational energy a bond contains [ internal energy of the bond ], the more external energy it requires to break a bond [ this is the dissociation energy ]. It is also found that the larger force constant that a compound has the stronger is the vibrational energy and the more amount of energy it is required to break the bond. NaCl is an anomaly in this respect. This compound shows a steady increase in vibrational energies but a low dissociation energy to break the bond

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The graphs of 5 compounds of varied characteristics are plotted altogether. NaCl which has a rock salt crystal structure shows the least amount of vibrational energy. HF is a gas and HCl is a liquid but they are both hyfrogen halides. They show the largest amount of vibrational energies. HgSe and ZnS seem to have similar levels of vibrational energies. ZnS has a Zinc Blende crystal structure and HgSe has a sphalerite crystal structure. Thus the order of vibrational energies go like this:HF(Gas) > HCl (liquid)> NaCl( rock salt crystal structure)> ZnS (Zinc Blende crystal structure)> HgSe (sphalerite)The dissociation energies also show similar orders : HF(Gas) > HCl (liquid)> NaCl( rock salt crystal structure)> ZnS (Zinc Blende crystal structure)> HgSe (sphalerite).

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NaCl molecule show a reduction in dissociation energy with increase in distance from equivalent position. Hence it is easier to dissociate Sodium and Chlorine. One probable reason for such a low dissociation energy required to dissociate Na and Cl is due to the formation of a Rock Salt structure from FCC structured constituents.

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Chlorine also depicts a peculiar dissociation energy graph. Unlike other molecules, the dissociation energy does not start right from nearly 0 magnitudes. Chlorine molecule seems to need a considerable amount of dissociation energy from the nearest distance from equivalent position. Chlorine molecule seems to have good bond strength. It takes a large amount of energy to dissociate the two chlorine atoms

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The internal energies inside a molecule comprise of various forces and dissociating the atoms in a bond needs manipulation of each of these energies.

Thank you

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REFERENCE:FTIR studies of PVC/PMMA blend based polymer electrolytes.S. Ramesh et al, 19 June 2006FTIR-ATR-based prediction and modelling of lignin and energy contents reveals independent intra-specific variation of these traits in bioenergy poplars.Guanwu Zhou et al, 2011FTIR and FT-Raman Spectral Analysis of Pacilitaxel DrugT.S Renuga Devi and S. GayatriFTIR and Conductivity Studies of PVC Based Polymer Electrolyte Systems.S. Rajendran and T. UmaRemediation of Hydrocarbon Contaminated Soil through Microbial Degradation- FTIR based prediction. Mohd. Muzamil Bhat1 et al Studies on Electrochemical Properties and FTIR analysis of Epoxy Polyester Hybrid Coating System. K. Ramesh et al, Centre for Ionics University of Malaya, Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, MalaysiaFTIR Studies on Silver-Poly(Methylmethacrylate) Nanocomposites via In-Situ Polymerization Technique. Noorsaiyyidah Darman Singho et al. Nanomaterials Engineering Research Group, Advanced Materials Research Laboratory, Department of Mechanical Engineering, University of Malaya, Lembah Pantai, Kuala Lumpur, 50603 MalaysiaVibrational properties of LaPO4 nanoparticles in mid- and far-infrared domain, P. Savchyn et al, 19 December 2012Impedance Spectroscopy and FTIR Studies of PEG - Based Polymer Electrolytes.ANJI REDDY POLU and RANVEER KUMAR, 23 July 2010Raman scattering and FT-IR spectroscopic studies on dithienylethene switches—towards non-destructive optical readout.Jaap J. D. de Jong et al, published as an Advance Article on the web 22nd May 2006Nanostructures and Nanomaterials, Gouzhong CaoX-Ray Diffraction: a powerful method of characterizing nanomaterialsRavi Sharma et al , 2012Interatomic force constants of semiconductorsV. KumarTheoretical study of small clusters of Iron-doped Group III antimonides- Fe (M-X) whereM=Al, Ga & In and X-SbApoorva Dwivedi, Saurabh Pandey, Neeraj MisraAtomic Structures of a Monolayer of AlAs, GaAs, and InAs on Si(111)Geunjung Lee and Young-Gui Yoon