Of course, probably nobody has really measured this at such extreme temperature; but from the data coming with FactSage one can calculate activities (= vapor pressure). It is plotted in the file attached here. Aluminum comes also as dimer, which is plotted too.

Detlef Klimm Sir,

Thanks a lot for this useful and interesting data

Can be found on the net up to 4000K

2)

You have also some answers in Wikipedia

http://en.wikipedia.org/wiki/Vapor_pressures_of_the_elements_%28data_page%29

Thanks sir