get_Rstd: Return heavy-to-light isotope ratio of primary standard.
Description
Returns the heavy-to-light isotope ratio of the dominant
standard for that element. Vienna Standard Mean Ocean Water
(VSMOW) for oxygen and hydrogen isotopes, Vienna Pee Dee
Belemnite (VPDB) for carbon stable isotopes.
Usage
get_Rstd(element)
Value
Heavy-to-light isotope ratio of most common
stable isotope standard. VSMOW for water,
VPDB for carbon.
Arguments
element
Which element to return standard ratio -
carbon, oxygen, or hydrogen.