The database java applet can be found on the Rate99 web site at the following URL: http://www.rate99.co.uk. The user can perform searches for reactions which
The searches can be made either on the whole database, or on the current results.
Information on an individual reaction can be displayed by selecting that reaction from the results list. The information displayed is an expansion of the flag field (see Sect. 3.1), and includes the formula for calculating the rate coefficient of the reaction, the reference from which the data are sourced and the temperature range over which the data are valid. At this point a graph can also be displayed showing the variation of the reaction rate with temperature, or in the case of interstellar photoreactions (PHOTON) or photoreactions induced by cosmic-rays (CRPHOT), the variation with visual extinction or grain albedo respectively.
A major function of the applet allows the user to build a ratefile interactively by choosing which elements and/or species it is to be composed from and optionally which temperature it is to be used for.
The current ratefile or selection of reactions can be saved at any time onto the user's local machine for use with an equation writer (the format of this file is described in Sect. 3.1). Normally, java applets are denied access to the local filesystem for security reasons. When the applet wants access to the filesystem, the user is alerted and can either grant or deny this permission. For this to work, the browser must support Java 1.1 or later. The implementations of security are (naturally) different between Netscape and Internet Explorer, so to begin with the applet only works with Netscape Navigator v4.5 or above. All this is explained in further detail on the web page itself.
Acknowledgements
We are grateful to all the people who made constructive suggestions and generously provided us with new data sources, particularly Dr. V.G. Anicich who provided an electronic version of his reference list which has been incorporated into the web version of the database, and Dr. J.H. Black whose detailed referee's report enabled us to make significant improvements to the database. Astrophysics at UMIST and the work of YHLT in particular are supported via a grant from the Particle Physics and Astronomy Research Council (PPARC). AJM thanks PPARC for a studentship.
Copyright The European Southern Observatory (ESO)