ACKNOWLEDGEMENTS

First and foremost, I thank Almighty for showering his grace to

makethis endeavor possible.

At the outset, I thank our Vice-Chancellor of Periyar University,

Salem-l l , for having given me the good opportunity to do my Ph.D Degree

course in this esteemed University.

I wish to express my sincere thanks and gratitude to my beloved

guide Dr.P.M.ANBARASAN, M.Sc., M.Phil., Ph.D., Reader in Physics,

Periyar University, Salem-ll, for his extensively stimulating constructive

guidance, utmost motivation, inspiring comments and suggestions

throughout the period of my research work. As an admirable and

approachable person, he has rendered me a great help in all possible ways.

Personally he has shown a care and concern which I may not get from

anyone else. It has been a pleasing experience to work under his guidance.

I remain forever grateful to him. I am very happy to say that I am a student

of Dr.P.M.ANBARASAN. Really, I can say, his smiling encouragement

is the backbone for my research.

I wish to place my hearty and sincere thanks to my respectable

Prof.Dr.V.Krishnakumar, M.Sc, M.Phil, Ph.D., Professor and Head of the

Department of Physics, Periyar University, Salem for his constant

encouragement, kind blessings, wealthy advice and administrative support

given in all aspects during the period of research work.

I would like to thank the faculty members of the Department of

Physics, Periyar University, Salern-l l for their valuable advice and

encouragement during entire period of research work.

The Office Staff members of Dept. of Physics, Periyar University

are warmly acknowledged with thanks for their constant help and fine

co-operation.

I am ever indebted sincere thanks to Prof.Dr.S.Mohan,

Vice-Chancellor of PRIST University, Tanjore and Dr.N.Sundaraganesan,

Reader in Physics, Annamalai University, Chidambaram, for their help and

encouragement at all time of my research work.

As long as I'm writing names down, I cannot neglect that of my best,

most constant friend Dr.V.Ilangovan, Asst. Professor of Physics, Tagore

Arts College, Puducherry, for providing me a lot of support and

encouragement during the period; he's a great guy and I don't want to miss

anopportunity to get that in the permanent record.

My affectionate thanks are due to Prof.Dr.A.K.Ramasamy,

Professor and Head, Dept. of Chemistry, Periyar University and

Dr.S.Venkateswaran, Reader in Geology, Periyar University for

encouragingme to pursue the research after my master degree.

I can never find words to express my sentiments for the co-operation

and encouragement that I had from my beloved Principal

Dr.S.SEETHARAMAN M.Sc., M.Phil., Ph.D., .Thiruvalluvar Govt. Arts,

Rasipuramduring my course.

I would like to thank the faculty members of the Department of

Physics, Government Arts College (Autonomous), Salem-7 especially

Prof.Dr.T.K.Vasudevan,Mrs.K.Murugeswari,Mrs.K.Managaiarkarasai

and Lab assistants for their valuable advice and encouragement during

entireperiod of research work.

My special and sincere thanks to faculty members and Lab assistants

of Dept. of Physics, Thiruvalluvar Govt. Arts College, Rasipuram for

their help and blessings at all time of my research work - Special mention

must be made of my best friend Dr.P.Duraisamy.

It is a pleasure to acknowledge the assistance derived from my

friends Dr.S.Duraisamy, Er.N.Manickam, Mr.P.Perumal, Dr.P.Duraisamy,

Mr.A.Poyyamozhi, Mr.K.Selvaraju, Mr.N.Senguttuvan, Mr.P.Dhayanidhi,

.Mr .K.Kanagasabapathy ,Mr. S.Alexander,Mr. V .Mahadevan,Dr.R. Sivakumar

Dr.P.Sundaramoorthy, Dr.A.Thennarasu and Mrs.S.Manimegalai for

inspiring me in various stages.

With deep love, I wish to thank a host of other friends and well-

wishers in and out of Salem who have encouraged and helped me during the

course of Research.

My interest in Science and Mathematics started early in my life, and

my parents encouraged and educated me in ways both straightforward and

devious. I acknowledge with great pleasure the unflinching support given

by my beloved Parents Mr. M. Karuppa Gounder, Mrs. P. Perumayee,

to. whom this thesis is dedicated, Sisters Mrs.K.Kamalam &

Mrs.K. Thilagavathy, my wife Mrs.A.Tamilarasi, M.A., M.Ed., D.T.Ed.,

and my children T.S.Kavinesh Sankar &T .S.Mounish Sankar without

which this research work would not have been materialized. My SIncere

thanks for their immense patience, prayers, affection and moral support

throughout the period of my research work.

Place: Salem-l l

Date: 22.12.2008 M.K.Subramanian