NQRS

Nuclear Quadrupole Resonance Spectra Database

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NQRS
General description

Nuclear Quadrupole Resonance Specroscopy (NQRS) is a counterpart of NMR spectroscopy for molecular and solid-state research. Essentially, NQRS gives the magnitude of the electric field gradient that is produced by other nuclei and electrons surrounding the particular nucleus being focused. Some of the information that are obtained from NQR spectra are

  1. Nature of the chemical bond in which the target nucleus (atom) is involved, such as mode of orbital hybridization, Evaluation of assumptions used for quantum-chemical calculation of electronic structure of molecules.
  2. Detection of phase transitions of solid materials through changes of site symmetry and assessment of the order of the transitions.
  3. Number of inequivalent molecules and ions in a unit cell.
  4. Identification of chemical species and crystal modification.
  5. Simple, straightforward assignment of quadrupolar splitting of NQR spectra in the solid state.

Interaction between a nucleus having a nuclear quadrupole moment and the electric field gradient which arises from arrangement of electric charges around the nucleus being focused. Nuclei having a spin greater than 1/2 possess an electric quadrupole moment are the targets of the spectroscopy. Examples include D-2, B-11, N-14, O-17, Cl-35, Br-78, Sb-121, and I-127. NQRS provides a unique non-destructive analytical tool for solid materials because it usually gives a very sharp lines characteristic of a particular solid in its particular state of aggregation.

NQRS Database covers all articles reporting either resonance frequencies or nuclear quadrupole coupling constants in numeric form (also in graph form since 1996). The database contains more than 14,500 entries reported since 1950, the year of the discovery of the spectroscopy. There are quite a few records in the database which report measurements on high temperature superconductors and chlorine-containing environmental substances.

NQRS Database is a result of endeavor for data compilation by a team of specialists in this discipline with international support from NQRS scientists. The Database is provided with a load/search software on CD, You can search and display the full content of the NQRS Database on your personal computer. The search fields include Molecular Formula, Chemical Name, CAS Registry Number, Mass Number, Author Name, Year of Publication, Journal CODEN, Keywords, and Keyphrase.

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Trial use

A trial CD for evaluation is available upon request.

  
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Sample output

Record number; 6138
FORM 77890-78-9 C45H76Cl6N2O2
NAME 1 1-Butanamine, N,N,N-tributyl-, salt with 2,2'-methylenebis[3,4,6-
NAME 2 trichlorophenol] (2:1);
AUTH Babushkina T A; 1
JRNL IANFAY Izv Akad Nauk SSSR Ser Fiz; 45; 3; 1981; 525; 527; 1

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      Nucl.
 Method Mass Temp/K  Ref                  Freq/MHz
    P    35    77.    1    36.540  36.460  36.232  36.151  35.798  35.637 
    P    35    77.    1    35.406                                              
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Structure of the Database
  1. Substance information
    Molecular formula is given by the Hill system. It can be searched in full or in truncated form. Chemical name is in systematic nomenclature (IUPAC or CAS) and/or common, trivial name. Truncation is possible for searching, e.g. "ethyl" or "benzo" can be a search term. CAS Registry Number is searchable.

  2. Spectral data
    Nuclear mass number, method of measurement, temperature, and resonance frequencies. All of these data are displayable. Searching in terms of a range of frequency is a unique feature of the NQRS database, e.g. "35 24.56-24.62" may be used as a search term for chlorine resonance to be found between 24.56MHz and 24.62MHz. Quadrupole coupling parameters are given in REMK field, which is displayable.

  3. Journal reference information
    Author name, journal name, journal CODEN, year of publication, and other bibliographic information are given.

  4. Auxiliary information

  5. Remark field displays additional information about the substance and about the measurements such as the method of preparation, crystalline modification, extraordinary properties of the substance. Quadrupole coupling constants and the asymmetry parameter are recorded in this field if reported in the original literature. There is KEYWORD field which is searchable. A single keyword, which may be truncated, or a key-phrase is a search term.
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Delivery

The database with search/display software is distributed on a CD.

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Updates

The database is updated twice a year, in April and October. Updating is done by adding new records, replacing old data with more accurate, recent data, and integrating new data into an existing entry for the same substance.

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Price
  1. For inhouse use: Annual license fee including handling charge and postage
    USD 1,870. (USD 670 for academic subscribers)

  2. For public service: Annual license fee including handling charge and postage
    License: USD 1,870
    Hit charge: USD 0.10/logical record
    Replication charge: USD 0.15/logical record/copy
    Prices are subject to change without notice.

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Ordering information

Orders should be sent to JAICI. Upon receipt of order, License Agreement forms will be mailed for signing. Payment must be received before a CD is delivered.

  
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