Search results
Results from the WOW.Com Content Network
D 0 is number of atoms of the daughter isotope in the original or initial composition, n is number of atoms of the parent isotope in the sample at the present, λ is the decay constant of the parent isotope, equal to the inverse of the radioactive half-life of the parent isotope [6] times the natural logarithm of 2, and
Here, R A is the isotope amount ratio of the natural analyte, R A = n(i A) A /n(j A) A, R B is the isotope amount ratio of the isotopically enriched analyte, R B = n(i A) B /n(j A) B, R AB is the isotope amount ratio of the resulting mixture, x(j A) A is the isotopic abundance of the minor isotope in the natural analyte, and x(j A) B is the ...
Stable isotopes partitioning between two substances A and B can be expressed by the use of the isotopic fractionation factor (alpha): α A-B = R A /R B. where R is the ratio of the heavy to light isotope (e.g., 2 H/ 1 H or 18 O/ 16 O). Values for alpha tend to be very close to 1. [1] [2]
An example is water, whose hydrogen-related isotopologues are: "light water" (HOH or H 2 O), "semi-heavy water" with the deuterium isotope in equal proportion to protium (HDO or 1 H 2 HO), "heavy water" with two deuterium atoms (D 2 O or 2 H 2 O); and "super-heavy water" or tritiated water (T 2 O or 3 H 2 O, as well as HTO [1 H 3 HO] and DTO [2 ...
The equations can be used to describe an isotope fractionation process if: (1) material is continuously removed from a mixed system containing molecules of two or more isotopic species (e.g., water with 18 O and 16 O, or sulfate with 34 S and 32 S), (2) the fractionation accompanying the removal process at any instance is described by the ...
Equilibrium isotope fractionation is the partial separation of isotopes between two or more substances in chemical equilibrium. Equilibrium fractionation is strongest at low temperatures, and (along with kinetic isotope effects) forms the basis of the most widely used isotopic paleothermometers (or climate proxies): D/H and 18 O/ 16 O records from ice cores, and 18 O/ 16 O records from calcium ...
Isotopic shifts are best known and most widely used in vibration spectroscopy, where the shifts are large, being proportional to the ratio of the square root of the isotopic masses. In the case of hydrogen, the "H-D shift" is (1/2) 1/2 ≈ 1/1.41. Thus, the (totally symmetric) C−H and C−D vibrations for CH 4 and CD
Archaeological materials, such as bone, organic residues, hair, or sea shells, can serve as substrates for isotopic analysis. Carbon, nitrogen and zinc isotope ratios are used to investigate the diets of past people; these isotopic systems can be used with others, such as strontium or oxygen, to answer questions about population movements and cultural interactions, such as trade.