[texhax] Re-defining \.{}

[Simmie, John]

Phil Taylor kindly redefined the $\mathrm{...\dot{X}...}$ command for me
to emphasise the period 
over a chemical element name which indicates an unpaired electron.

In the preamble he suggests

\let \canonicaldot = \dot
\let \canonicalperiod = \.
\def \dot #1{{\bf \canonicaldot {\rm #1}}} \message {\meaning \.}


But occasionally one uses the same convention outside of math mode, for
example
 to show a hydroxyl radical  \.{O}H 

Is there a relatively simple one-time fix for this latter? 
This       \bf{\.{O}}H    would do but is somewhat clunky

Emeritus Professor John Simmie::Combustion Chemistry Centre::NUI Galway,
Ireland