Since .xmp files do not contain any graphics data, just metadata, it is not possible to convert any picture or photograph (including .raw) to it. However Photoshop apps can generate .xmp files as part of the processing of raw digital photographs. So this operation is not conversion, but standard Photoshop operation procedure.
Convert Digital camera photo RAW image format to Adobe Extensible Metadata Platform file.
We found 3 software records in the database related to .raw to .xmp file format conversion.
Microsoft Windows software - convert raw to xmp on Windows
Adobe's professional tools for RAW image management and post-production
Convert from raw file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned raw to xmp. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
A RAW import plug-in for Adobe Photoshop
Apple macOS / Mac OS X software - convert raw to xmp on OS X
Mac version of Adobe' professional digital photo editing tools