Laser absorption measurement for clumped isotopes

摘要

In one embodiment, an apparent equilibrium constant involving a clumped isotope in a gaseous sample is measured by acquiring sample spectra of portions of the gaseous sample at different pressures. An external bulb coupled to a sample cell is filled with the gaseous sample. A first portion of the gaseous sample is transferred from the external bulb to the sample cell, where it is at a first pressure. A first sample spectrum is obtained. Then, a second portion of the gaseous sample is transferred from the external bulb to the sample cell, where it is at a second, different pressure. A second sample spectrum is obtained. An apparent equilibrium constant for the clumped isotope is calculated by determining a first isotopic ratio at the first pressure, determining a second isotopic ratio at the second pressure, and taking a product of the first isotopic ratio and the second isotopic ratio.

主权项

1. A method for measuring an apparent equilibrium constant involving a clumped isotope of a molecule in a gaseous sample, comprising:
filling a sample cell of a laser absorption spectrometer with a first portion of the gaseous sample, the first portion of the gaseous sample being at a first pressure; acquiring a first sample spectrum of the first portion of the gaseous sample; transferring a second portion of the gaseous sample from an external bulb coupled to the sample cell into the sample cell, the second portion of the gaseous sample being at a second, different pressure; acquiring a second sample spectrum of the second portion of the gaseous sample, and calculating the apparent equilibrium constant involving the clumped isotope of the molecule based on the first sample spectrum and the second sample spectrum acquired at different pressures.