[R] Isotopic notation in plots

[Robert W. Baer, Ph.D.]

From: "Christophe Declercq" <cdeclercq at nordnet.fr>
> Try:
>
> > plot(1:10,xlab=expression(phantom(0)^{14}*C))

Just out of interest, how do I find out what phantom(0) does?  I tried both
?phantom and help.search("phantom") without getting any hits, and yet the
expression posed above creates a leading blank space in the axis label.  I
take the latter to mean that phantom() is available withinin the basic
packages (search path).

Where do I read more?

Thanks,
Rob