Changes to make Particles consistent with ChemicalElements
Changes to make Particles consistent with ChemicalElements

# Now that the checker supports the more standard {}^{...}_{...} syntax, rather than
# the slightly weird ^{...}_{...} syntax, use it preferentially.

ucam-cl-dtg/isaac-app,ucam-cl-dtg/isaac-app,ucam-cl-dtg/isaac-app,ucam-cl-dtg/isaac-app