Alternating gradient focusing and deceleration of large molecules

TL;DR

This paper demonstrates the successful focusing and deceleration of large asymmetric top molecules, specifically benzonitrile, using an alternating gradient electric field technique, showing the method's applicability to complex polyatomic molecules.

Contribution

It introduces the application of alternating gradient Stark deceleration to large polyatomic molecules like benzonitrile, expanding the scope of molecular control techniques.

Findings

Benzonitrile molecules were decelerated from 320 m/s to 289 m/s.

The experimental results matched trajectory calculations.

Large polyatomic molecules can be effectively manipulated using Stark deceleration.

Abstract

We have focused and decelerated benzonitrile (C$_7$H$_5$N) molecules from a molecular beam, using an array of time-varying inhomogeneous electric fields in alternating gradient configuration. Benzonitrile is prototypical for large asymmetric top molecules that exhibit rich rotational structure and a high density of states. At the rotational temperature of 3.5 K in the pulsed molecular beam, many rotational states are populated. Benzonitrile molecules in their absolute ground state are decelerated from 320 m/s to 289 m/s, and similar changes in velocity are obtained for excited rotational states. All measurements agree well with the outcome of trajectory calculations. These experiments demonstrate that such large polyatomic molecules are amenable to the powerful method of Stark deceleration.