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Construction of this page Started on the Sunday, Nov.09, 2008 &nsp; Addition of IBS2009 materials since Jan. 10,2009 Addition of NSC-11 materials since Feb.03,2009 Last update by Aravamudhan at Shillong, on March 03, 2009
Participation in the 96th Indian Science Congress at NEHU, Shillong from 3-7, January 2009
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Images copied from the WebSite for NMRS2009
Dr.S.Aravamudhan Logo "NMRS2009"
Link:- The First Bruker Pre-NMRS Symposium in INDIA
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CLICK HERE and find updated [as received from organizers on 6th Jan.2009] list of participants, titles of abstracts, accommodation request and details of their travel.The same information will be posted on webpage (www.nmrs2009.org/linked to image above) Entry Number(S.No) 158 in the list is as below; 158 M DR. ARAVAMUDHAN SANKARAMPADI GUEST PROF. NEH UNIV.,SHILLONG 2 5 Y N   inboxnehu_sa@yahoo.com  THE NECESSITY FOR A PROTOCOL FOR PROCESSING AFTER EXPERIMENTAL MEASUREMENT OF PROTON SHIELDING TENSOR IN SINGLE-CRYSTAL SPECIMEN
posted at Kolkata Airport on 7th Jan.2009 at 3:47 PM
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Abstract for NMRS2009 Jump to IBS2009
CLICK HERE to download the MSWORD document of the Abstract_nmrs2009
Scientific Program List of people presententing abstracts
THE NECESSITY FOR A PROTOCOL FOR PROCESSING AFTER EXPERIMENTAL MEASUREMENT OF PROTON SHIELDING TENSOR
IN SINGLE-CRYSTAL SPECIMEN
S.ARAVAMUDHAN
Department of Chemistry
NORTH EASTERN HILL UNIVERSITY
SHILLONG 793022 Meghalaya
The context here is the measurements of Shielding Tensor of protons in solid-state single-crystal specimen. The experiments yield the values of the components and the direction cosines of the principal directions of the Tensor. Further after, In order to obtain the information on the molecular electronic properties (in the case of single crystals of organic molecules) it becomes necessary to properly account for the near neighbor inter molecular contribution to the shielding at a given site; and the bulk susceptibility contribution to the induced fields at this site. Thus, the subsequent processing, required after obtaining the experimentally measured values, has been a discouraging factor in the HR PMR studies using the multiple pulse line narrowing techniques. This has relegated such HR PMR studies even more because of the current day advances in the multi nuclear multi dimensional techniques and the corresponding improvements in the spectrometer features. However, in spite of all such trends and improvements there has been no unequivocal evidence(1) that there would not be situations arising when a structural characteristic can be established only with the HR PMR measurements also made for conclusive evidences. Such situations may not be a routine these days, but still there is a necessity to provide a protocol for the processing after the experimental measurement (2).
An enumeration of the results till now is intended in this contribution envisaging a protocol for measurements by HR PMR using multiple pulse line narrowing technique. The various steps taken till now to obtain clarifications(3) on the accounting of bulk susceptibility contributions(4) are enumerated systematically realizing a protocol which would be valid for any shape of the specimen of all molecular systems for which a single crystal can be obtained(5).
1. http://www.geocities.com/saravamudhan1944/eenc_ampere_lille.html#Section_4
2. http://nehuacin.tripod.com/id4.html ) (EUROMAR2007)
3. http://nehuacin.tripod.com/id6.html (FD NMR; Sheet-10 of display sheets)
4. http://nehuacin.tripod.com/id3.html (4th Alpine SSNMR Conference)
5. http://www.geocities.com/inboxnehu_sa/nmrs2009.html
inboxnehu_sa@yahoo.com
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Materials for A POSTER PRESENTATION: Download Postersite Layout Acceptance of Abstract received on January 15, 2009 while at Chennai
Sheet_10_11_12 Sheet_13
THE OVERALL PROCEDURE
DOWN LOAD "OVERALL PROCEDURE"
1. The sample is of arbitrary Shape.
2. Obtain a set of x, y, z coordinate values, which when tabulated can
conveniently provide the reconstruction of the shape of the specimen. This
could be a laboratory experiment (as described in Sheets #11 and #12 in this poster display) which has to be standardized by considering the specimen of typical shapes and the requirements for the Calculation of bulk susceptibility effects as described in Sheets #7 and #8 of this display.
3. Orient the specimens and make the HR PMR measurement to obtain the rotation pattern. Compute for the Principal Directions and Component values of the measured Shielding Tensor.
4. Calculate the inter-molecular contribution to shielding tensor by discretely summing within a semi micro volume element as described in Sheets #2, #3, #5. Subtract this inter-molecular contribution from the measured experimental Tensor values.
5. Calculate the shape-dependent values due to the bulk susceptibility effects as described in Sheets #7 and #8. Subtract this calculated tensor for shape dependent contributions from the result of step 4 above.
6. The value of the tensor obtained as a result at stage 5 should be the required INTERMOLECULAR SHIELDING TENSOR.
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IBS 2009
During 27-31 Jan. 2009 Dr. Aravamudhan was at the IGNOU, New Delhi for consultations with the
Pro-Vice-Chancellor Prof. K.R. Srivathsan in connection with a "WORKSHOP ON E-LEARNING WITH
FOCUS TO EDUCATIONAL INTERNET DOMAINS" to be held at the Computer Centre, N.E.H.U. Some of the considerations on the theme for the workshop are included in the Downloadable link : E-Learning Workshop
This document essentially describes the needs as does arise for students with educational backgrounds from the North Eastern Region
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The materials for presentation in IBS2009 are based essentially on the materials of the IBS2007.
This author could not attend the IBS2007 due to turn of events beyond control hence the materials remained unpresented. The Poster materials of IBS2007 can be viwed from HERE,..Click!
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POSTER SITE of IBS2009 created on Wednesday, January 21, 2009 at IICT Guest House, Hyderabad--S.Aravamudhan
POSTER SITE IBS2009:NCMB2009
Poster #P94 CLICK HERE to display the list of Abstracts as extracted from the URL: http://ccmb.res.in/ibs_2009/abstract.pdf and added to this page on 21 Jan. 2009 at 11:50 AM
ABSTRACT: IBS2009 Find on page 92 of the NCMB-2009 Symposium ABSTRACTA BOOK
FULL TENSOR FORM FOR CALCULATING RING CURRENT SHIFTS GENERATING WEIGHT FACTORS OF THE INSTANTANEOUS CHEMICAL SHIFT VALUES FOR AN EFFECTIVE MOTIONAL AVERAGING IN BIOLOGICAL MOLECULES
S. ARAVAMUDHAN
Department of Chemistry
North Eastern Hill University
SHILLONG 793022 Meghalaya
inboxnehu_sa@yahoo.com
By using the Full Tensor Form of the equation for the aromatic ring current shifts in the , it has been possible to show (1) that there are definite advantages of calculating the full shielding tensor for such cases of molecules in motion, rather than merely using the equations for the isotropic shift values. However, in the model calculation presented (2) equal weights were given for the shift values sampled at the several instantaneous dispositions during the motion while arriving at a average value. Conventionally, an oscillatory motion (torsion) is satisfactorily taken into account on the basis of the characteristics of Simple Harmonic Motion. In such a case the characteristic resident time for the molecule at a point during the oscillation can determine the weight factor. Such criteria if it gets built in to the averaging procedure, then the results could have better confidence indices. An approach of this type would be illustrated and to whatever extent possible a comparison with the approaches as in Reference (3&4) would be presented. Indications to the observable trends in the chemical shifts become evident in the results obtainable in tabular form and or graphical plots.
Refrerences:-
(1). http://www.geocities.com/sankrampadi/ForIbs2006.html Poster Sheet_11:
(2). http://www.geocities.com/sankrampadi/ForIbs2006.html Poster Sheets_10 & 11:
(3). �Fluctuations and Averaging of Proton Chemical Shifts in the Bovine Pancreatic Trypsin Inhibitor�, Jeffrey C. Hoch, Christopher M. Dobson, and Martin Karplus, Biochemistry 21, 1118-1125 (1982)
(4). http://in.geocities.com/saravamudhan2002/events_2007.html
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SHEETS-01 to 03 consist of excerpts from an early application of isotropic ring current shift values to the context of macromolecular fluctuations. SHEET-04 describes the efforts initiated for the calculation of FULL TENSOR instead of only the trace.
Display SHEETS 05 to 09 contain the results of a calculation as per the considerations of SHM weight factors discussed in the Previous SHEET-03.
SHEET-09 consist the essential results as can be summarised till the present.
SHEETS 10 to 12 contain the results displayed in the previous years� IBS events on the necessity for the calculation of ring current shits in Full Tensor FORM. The illustrations in this presentation of the considerations on the trends in weight factors while averaging are once again mainly with isotropic calculation trends. But the results as presented indicate well how the differences can improve significantly the conclusions with appropriate option on the specific tensor component should be relevant and for such a specified component how the criteria for relative weight factors can be adapted
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This certificate uploaded on 28 Jan. 2009 at IGNOU, New Delhi
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NSC-11 11th National Symposium on Chemistry (of the CRSI): National Chemical Laboratory, PUNE February 5-8, 2009
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ABSTRACT NSC-11
AN APPROACH TOWARDS A DESCRIPTION FOR NQR PHENOMENON IN TERMS OF CLASSICAL VECTOR PRECESSION: An effort for the appreciation of Chemists, highlighting similarities and differences in the NMR and NQR Phenomena
S.ARAVAMUDHAN
Department of Chemistry
North Eastern Hill University
SHILLONG 793022 Meghalaya
inboxnehu_sa@yahoo.com
The induced transitions, in presence of the electromagnetic radiations in the Radio Frequency region responsible for Nuclear Quadrupole Resonance (referring explicitly to NQR at zero external magnetic field) are magnetic dipole transitions in nature as much as the NMR transitions are. But, the energy of interactions which cause the energy level splitting in the two cases are different. In the case of NMR it is the magnetic dipole vector interacting with the External Magnetic fields (external to the sample containing the ensemble of spins) which causes energy level splitting. On the other hand the basic interaction for the NQR is the Nuclear Quadrupole Moment Tensor with the Electric Field Gradient Tensor within the specimen, but external to the particular nucleus.
The classical vector precession picture can be conveniently used to convince in the Chemistry class rooms to get convinced about the parameters which are relevant to chemists.
But a similar visualization is not possi9ble for NQR as can be found from several sources. Efforts were made to use the classical vector description for the Bulk Magnetization in the context of NQR, but the classical vector description of the type of nuclear spin precession to describe NQR phenomenon is totally absent. It is because the nuclear quadrupole moment is described and discussed under nuclear physics and the Tensor interactions are describable conveniently by mathematical expressions but visualization of �tensors� is not as easy as the visualization of �vector� quantities.
In this paper the tensor interactions and the differences between Magnetic Field Vectors, and the Electric Field Gradient Tensors are being discussed by schematically representing the fields and field gradients in terms of the trends of the �lines of forces� representing the fields. Then the association of the magnetic moment with the spin angular momentum is compared with the difficult task of associating the spin angular momentum vector with the Nuclear Quadrupole Moment Tensor. After arriving at a �equivalent� description of an association of an effective line to represent quadrupole property (even though in reality such a line may not exist) that line is �supposed� to hold a fixed orientation with respect to the Spin angular momentum, by virtue of which a classical vector precession picture becomes tangible. And, this would really enable the necessary basics about the interactions in NQR to be grasped with an awareness as to why the descriptions cannot be as simple. Even though, even without such a study, pulsed NQR experiments are being performed and described in terms of density matrices and the utility of the phenomenon has been so well established. But the appreciation of the pulsed NQR experiments by the Chemists who use this technique remains only vague and elusive for the grasp. Hence descriptions as basic as that of dipole moments1 would be presented for the quadrupole moment to bring the phenomenon under better grasp. An indications to what this approach would be has been made available2 for viewing.
Reference:-
1. http://www.geocities.com/saravamudhan1944/crsi_6nsc_iitk.html
2. 2. http://in.geocities.com/saravamudhan2002/NMRS2008.html
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CLICK HERE to Download COPY of NSC-11 ABSTRACTS BOOK as ".pdf " file of 7MB Size This Abstract book was in the CD Form as part of the Registration Material
POSTER SITE NSC-11 NOTE:-The order in which these Poster sheets are arranged in the table below and the contents might be slightly different from the way the presentation was made on 7th Feb. 2009
INDEX to the Contents of Display Sheets
SHEET-01 CONTENTS INDEX
SHEET-02 & SHEET-03 INTRODUCTORY NQR
SHEET-04 DESCRIBING FIELD GRADIENTS
SHEET-05 Nuclear Charge Distribution: Spherical versus Non Spherical Non Spherical distribution of charge and the Quadrupole moment; The possibility of a linear arrangement for the Quadrupole
SHEET-06 Nucleus; Nuclear Quadrupole moment; and the Nuclear Spin Angular Momentum
SHEET-07 Interaction of the Dipole with Uniform Field and the Quadrupole with Uniform (linear) Field Gradient
SHEET-08 Disposition of the various vector quantities and the linear quadrupole moment of nucleus
SHEET-09 Quantization of Angular momentum while Quadrupole moment Interacts with Field Gradient
SHEET-10 A Energy Level Diagram for Comparing NMR and NQR interactions
SHEET-11 Envisaging a Precession Picture for NMR and NQR
SHEET-12 What is right and What is wrong with the Question in this Sheet ?
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