Measurement of small photodestruction rates of cold, charged biomolecules in an ion trap

TL;DR

This study measures very low photodestruction rates of cold, charged biomolecules in an ion trap, demonstrating linearity with laser intensity and enabling future high-resolution spectroscopic analysis.

Contribution

It introduces a method for precise measurement of small photodestruction rates of cold biomolecules in an ion trap, with potential for high-resolution spectroscopy.

Findings

Destruction rates less than 0.05 s^-1 measured

Cross section determined as (1.1 +/- 0.1) * 10^-17 cm^2

Rates are linear in laser intensity

Abstract

In this work, we demonstrate measurements of photodestruction rates of translationally cold, charged biomolecules. The long-term stable storage of the molecular ions in an ion trap at ultra-high vacuum conditions allows measurement of small rates and verification that rates are linear in photodestruction laser intensity. Measurements were performed on singly protonated molecules of the organic compound glycyrrhetinic acid (C30H46O4), dissociated by a continuous-wave UV laser (266 nm) using different intensities. The molecules were sympathetically cooled by simultaneously trapped laser-cooled barium ions to translational temperatures of below 150 mK. Destruction rates of less than 0.05 s^-1 and a cross section of (1.1 +/- 0.1) * 10^-17 cm^2 have been determined. An extension to tunable UV laser sources would permit high-resolution dissociation spectroscopic studies on a wide variety of cold complex molecules.