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Dr.S.Aravamudhan
Department of Chemistry
North Esatern Hill University
Shillong 793022 MEGHALAYA
India
Phone: 91 0364 272 2624
Fax: 91 0364 272 2500/255
0486
The on-set of a CSIR Scheme: The
approval of the sanction of a CSIR research scheme, on the basis of the earlier application by Dr.S.Aravamudhan,Principal
Investigator, has been recently conveyed by(letter dated 15.01.2002) the CSIR,New Delhi, with the date of commencement
being 01.01.2002. Further information at the website URL: http://saravamudhan.tripod.com/csir_schm_sa/
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the left side links-panel: "other related webpages")consists
of a list of the contributions in pususance of the title"Explaining the trends of Nuclear Shielding caused by Magnetic moments related to Susceptibilties"
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2003) the reports at the above link of "id12.html" are listed and particulars are posted at the tripod site: http://nehuacin.tripod.com/
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the particulars about a proposal under the UGC Innovation Programme
The
present state of the effort towards calculating the induced fields in and around the magnetized specimen is described in these
webpages. It seems it is necessary to apply this simple method to various Chemical,Physical and biochemical contexts and find
the way towards getting reasonable results in all the cases as is applicable for that context and findout whether simple looking
procedure really as convenient as valid as it portends to be. The peactical details of the simplicity of the method and the
procedures of calculations are not included herein and can be obtained by sending in a request for such a requirement.
Introduction
The present subject of research has inception at the instance
which made a breakthrough in the explanations of discrepancies repeatedly encountered while trying to account for the results
of experimental proton shielding tensor measurements by the Multiple Pulse Selective Averaging methods in Solid State
NMR.
This work ,particularly on the single crystals of Pyromellitic Acid Dianhydride, opened up -as was pointed out in the Discussions
of the published paper-two pronged investigation of the consequences:
1) To study the possibilities of calculating INTRA
(in exclusion of
the INTER)molecular contribution to the shielding tensors as arising due
to the induced fields by
simple point dipole contributions.
And 2) to find methods of extending the considerations of intermolecular calculations
to the whole macroscopic extent of the specimen instead of the only semi-microscopic (of about 100 Angstroms extent) elements.These
should enable the simple basis of dipole contributions to be understood more comprehensively from the intra- to intermolecular
consequences without the acompanying obscurities due to the involved mathematical procedures which render all the explanations
to be beset with a kind of abstractness which causes discomfitures while applying in Chemical contexts.
On the aspect (1)a
poster presentation could result at the Joint ISMAR-CA'98 held at the Techniche Hochlue Berlin in 1998. The aspect (2) above is the matter dealt with in the presentation at the 2nd Alpine Conference on Solid State NMR,Chamonix Mont-Blanc,France during 9-13 Sept.2001 .
All these aspects have been presented
(in steps) at the annual Symposia of the National Magnetic Resonance Society,INDIA
Hence the present achievement is founded firmly
on the results of the work as Post Doctoral Fellow during 1975-77,and the informations gathered by literature survey while
being at the NCL,Pune and the further supplementary assistance available in obtaining published reference materials from CSIR
labs.The earlier efforts to realise were all in the form of several M.Sc.,Project Works(each of only six months duration)
at the NEHU,Chemistry. A great deal remains to be inferred by intensive efforts and communicate them as publications in Journals.
The possible applications of these simple calculation procedureshave beenpointed out broadly in the poster presentation at
the XIII Internatinal Biophysics Congress in held in New Delhi in September 199 9 and this participation
was supported by an INSA grant. The
research results which are contained in the presentations are all the outcome of the work carried out during the tenure of
appointment as teacher in the Department of Chemistry , North Eastern Hill University, Shillong. The results are being further
pursued with the purpose of finalising them for publication in refereed Journals.Most of the efforts had been resulting only
in a single author presentations.The publication includes an earlier Presentation in XIII International Biophysics
Congress and related Biopysical & Biochemical meetings.1]. The copy of the ABSTRACT uploaded & submitted at the Webabstract
Submission box/page of the XIV I.B.C. is being included in these pages. A grant could forthcome form the organizers of the
2nd Alpine Conference on SSNMR for the participation.
S.Aravamudhan
Author of the
Contribution to XIV I.B.C
Lecturer,Department of Chemistry, North Eastern Hill
University, Shillong,Meghalaya,India
The following is the essential features on the basis of which an application to the University
Grants Commission,New Delhi was sent in the year 1981 for the grant of a Research Associateship to enable computations at
I.I.T.Madras but evenbefore any considerations by the UGC an appointment as Lecturer at NEHU made it possible to keep continue
the studies. An effort was also taken to work out a viable Ph.D., thesis research proposal of this subject which would have
fetched a degree to a capable student at the University
DETERMINATION AND APPLICATIONS OF CONTRIBUTIONS TO SHIELDING TENSORS
Shielding tensor contributions
can be obtained by experimental NMR studies on solid samples and from theoretical Calculations(1,6).Since it enables
the determination of the principal values for the shielding tensor rather than just the trace of the tenosr, this information
is more detailed than that obtained from NMR experiments involving the liquid state and thus provides more information on
the chemical environment(2).Applying these methods (mentioned in references 1&2) to ring current contributions to shielding
tensors could provide valuable additional information to what is already available(3).Such attempts could lead to further
information on possible NMR experiments(in liquids and solids)on macromolecules which could supplement informations available
from x-ray crystallography(3). Since some of the methods of obtaining the shielding tensor informations are related to different
aspects of magnetic susceptibility anisotropy values, such study could provide a possible method for obtaining consistent
sets of bond- and atom- susceptibility anisotropy values(4). The methods used for calculating shielding tensor contributions
(using susceptibility anisotropy values) could be extended to calculate demagnetizing factors in magnetic materials(5). It
is proposed to carry out detailed studies on obtaining such hielding tensor informations to be able to obtain information
on chemical structures and certain physical properties.
References: 1. U.Haeberlen,
"High Resolution NMR in Solids: Selective Averaging", Advances in Magnetic Resonance,Supplement 1, Academic Press (1976).
2.N.R.Jagannathan, S.S.Rajan and E.Subramanian, Current Science, Vol.63, page 743 (1972). 3.Stephen J.Perkins,"Application
of Ring Current Calculations to Proton NMR of Proteins and trans RNA", in 'BIOLOGICAL MAGNETIC RESONACE', Vol.4, page 193,
Edited by Lawrence J.Berliner & J.reuben, Plenum Press (1972). 4. W.H.Flygare, Chemical Reviews, Vol.74, page 653 (19740.
5. Project Report submitted to the Department of Chemistry,North Eastern Hill University (in partial fulfilment of the requirements
of the Degree of Master Of Science) by Debashish Dutta(1993),Sushmita Dhar (1994) and K.Yhom (1996). 6. M.Mehring, "High Resolution
NMR in Solid",Springer,Berlin (1983).
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Home The Foreground and the current trends of research activities of Dr.S.Aravamudhan [--index.html]
Page 1 Other Related Web Pages [--id12.html]
Page 2 The 2nd Alpine Conference on Solid State NMR,Chamonix Mont-Blanc, France, 9-13th Sept.2001[--id1.html]
Page 3 Contribution to ISMAR-CA '98 TU Berlin, Aug.1998 [--id2.html]
Page 4 The Summing procedure and the volume elements with the
Benzene Molecular perspectives [--id3.html]
Page 5 Shielding- and Demagnetization-factor Calculations [--id4.html]
Page 6
A Graphical Depiction of the Results on the Calculation of Demagnetization Factors [--id5.html]
Page 7 Explanation
and illustration of Induced Field Calculations at Points Outside the Specimen Close to it [--id6.html]
Page 8 Any
Spill Overs from OR to the nanostructures in materials? [--id7.html]
Page 9 Pictorial Depiction of Semimicro Volume
Elements Graphical Plots of Calculations [--id8.html]
Page 10 Contribution to the XIV International Biophysics Congress,Argentina
April 27-May 1, 2002 [--id9.html]
Page 11 Poster Presentation at XIV I.B.C. Buenos Aires [--id11.html]
Page 12 About the Author/Curriculam Vitae/List of Contributions
and Publications [--id10.html]
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