Русско-английский научно-технический словарь
• In absorption, where we are concerned [or where we have to deal (or to do)] only with the atoms in the ground state, ...
• It is safe to handle an acetone-air mixture containing 6.0 mole percent acetone.
• We are dealing here with both emission and absorption lines.
• Often we deal with the volume of a gas sample at two different temperatures.