Impact of Advances in Computing and Communications Technologies on Chemical Science and Technology Report of a Workshop (1999) / Chapter Skim
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12 Chemical Data in the
12 Chemical Data in the
Pages 178-189
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From page 178... ...
The loss of funding for a number of activities that provided information to chemists cuts in library budgets, reductions in central research laboratories by industries, changing funding priorities at federal agencies have all led to a reduction in the methods for finding needed data. Many libraries have had to cut out information specialists just when the increasing costs of journals have forced users to spend more time finding data.
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From page 179... ...
For the most part we do not have modeling code that determines the "reasonableness" of the values used as input, nor do we have data resources that can provide physical limits for otherwise unknown data. TYPES OF DATA RESOURCES To satisfy the needs discussed above will require changes in the way that data resources are managed.
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From page 180... ...
In the "retail" model of data usage, the difference between these types of data resources is not as important as it is when the "user" of the data is a modeling program. Even when there is direct personal use by a scientist, a lack of specific technical background to which the data relate may cause many of the same problems as would occur with direct computer usage.
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From page 181... ...
For many properties this requirement is addressed by a combination of data for related properties plus models. This is the approach taken by the Design Institute for Physical Property Data (DIPPR)
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From page 182... ...
In addition, both values are sign reversed. The problem of sign reversal is fairly common in the Beilstein electronic database and probably arises from the convention in much of the thermochemical data literature of giving a table of values as -^Hfor rather than showing the sign in the table.
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From page 183... ...
However, both determinations are based on different enthalpy of formation data for CF4. When the experimental values are corrected for the currently accepted CODATA value for the enthalpy of formation data for CF4, the results are -925.5 kJ/mol and -937 kJ/mol.
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From page 184... ...
The DIPPR database illustrates the difficulty of providing high-quality complete data. The level and quality of the effort in the DIPPR project have been very high and the project has been going on for more than 17 years with fairly extensive resources, and yet only 1,700 compounds (all stable species)
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From page 185... ...
While these questions can be answered by expert evaluation of the experimental methods, the differences between experimental methods and high-level calculations, this level of evaluation cannot be done automatically, , ~ TABLE 12.2. Attributes of the NIST Chemistry WebBook Version Data Type34 5 Gas-Phase Ion-Energetics Data14,20014,30014,300 Gas-Phase Thermochemical Data2,8005,8006,100 Condensed-Phase Thermochemical Data4,6005,3005,500 Phase-Change Thermochemical Data8,8009,4009,500 Reaction Thermodynamic Data7,4008,7009,400 IR Spectra5,2005,2005,200 Mass Spectra8,30010,60010,600 Fluid Property Data Sets131616 Vibrational/Electronic Spectra & Energy Levels 2,6003,300 Spectroscopic Constants of Diatomic Molecules 600600 Total Species with Data27,30031,60032,400 Release DateAug-97Mar-98Nov-98
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From page 186... ...
The answer lies in part with the level of effort indicated by the DIPPR data project. If these data are important, then the effort needs to be made.
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From page 187... ...
The WebBook, DIPPR, and Beilstein are currently not equipped to handle direct requests from modeling programs. The need for communication standards among modeling programs and the databases that they rely on has not been touched on here, but the absence of agreed-upon query structure that would make it reasonable for a database provider to support direct access by modeling programs is not the real limiting step for future use of the data.
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From page 188... ...
David Dixon, Pacific Northwest National Laboratory: What is the structure of the database, and what were the manpower requirements to do the electronic version as compared to the manpower already working on the standard printed versions from which much of the electronic versions are derived?
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From page 189... ...
So that is relatively inexpensive and fairly cost effective because it really just takes somebody with good data entry skills to put it in a spreadsheet, and we do a little processing on it. One person works full time on the database itself.
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