Aarhus University Seal / Aarhus Universitets segl

Andrew Cassidy

Center Manager

Center for Interstellar Catalysis

Department of Physics and Astronomy (IFA) 
Aarhus University  
Ny Munkegade Build. 1520 
DK-8000 Aarhus C  

Office: 1520-326
Phone: +45 8715 5584
Email: amc@phys.au.dk  

Research Highlights

Low temperature aging in a molecular glass: the case of cis-methyl formate

Phys. Chem. Chem. Phys., 2021, 23, 15719-15726

The spontaneously generated electric field in a molecular glass, decays with time at deeply supercooled temperatures. Here, we fit the rate of decay with a model to extract the activation barrier to molecular rotation, as the glass ages.

A mechanism for ageing in a deeply supercooled molecular glass

Chem. Commun., 2021,57, 6368-6371

Cover Page

A molecular glass spontaneously polarises upon growth. The temporal decay of this polarization is directly related to the rotation of molecular dipoles and we use this to track an ageing pathway in a deeply supercooled glassy solid.

Comment on “Spontaneous Polarization of Cryo-Deposited Films for Five Normal Saturated Monohydroxy Alcohols, CnH2n+1OH, n = 1–5”

J. Phys. Chem. B 2021, 125, 27, 7568–7569

Graphene and graphene oxide on Ir(111) are transparent to wetting but not to icing

Carbon Volume 174, 15 April 2021, Pages 396-403

Graphene oxide on Ir(111) has a lower freezing onset temperature than pristine graphene on Ir(111).

Crystallites and Electric Fields in Solid Ammonia

Chemistry Open Volume9, Issue10  2020 Pages 983-990

Cover page

What do we mean when we describe a film of vacuum-deposited material as amorphous and what by crystalline? In this study of spontaneously electrical solid ammonia, we show that the so-called “amorphous” phase, prepared between 20–50 K, is a crystalline material composed of crystallites containing >64 molecules. More broadly, we introduce a technique to quantify the size of crystallites in nanoscale films.

Acceleration of ion recombination reaction rates in cold dark clouds through spontaneous polarization charge on CO ice mantles

Proceedings of the International Astronomical Union, 15(S350), 390-391

Low-temperature synthesis of a graphene-based, corrosion-inhibiting coating on an industrial grade alloy

Corrosion Science Volume 152, 15 May 2019, Pages 1-9

A low temperature, molecular polymerisation recipe generates a graphene coating on an industrial alloy and prevents substrate degradation. The coating reduces corrosion current by two orders of magnitude in acidic conditions.

Challenges for continuous graphene as a corrosion barrier

2019 2D Mater. 6 022002

We present a review discussing the use of graphene as a corrosion prevention technology. Corrosion, the degradation of metals and alloys by chemical and/or electrochemical means, is a great challenge to society, its industries and its citizens, both in terms of economics, safety and health. 

Hydrogen interaction with graphene on Ir(1 1 1): a combined intercalation and functionalization study

J. Phys.: Condens. Matter 31 085001

We demonstrate a procedure for obtaining a H-intercalated graphene layer that is found to be chemically decoupled from the underlying metal substrate.

The optical absorption spectra of spontaneously electrical solids: the case of nitrous oxide

Phys. Chem. Chem. Phys., 2019,21, 1190-1197

Mud flats, Fejø, Denmark: a 2D representation of defect-free regions in a molecular crystal that can support Wannier–Mott excitons.

Adsorption of 5-Fluorouracil on Au(111) and Cu(111) surfaces

AIP Advances 9, 085318 (2019)

The adsorption of 5-Fluorouracil (5FU) on Au(111) and Cu(111) surfaces as a function of molecular coverage and temperature has been studied, using x-ray photoelectron spectroscopy (XPS) and near-edge x-ray absorption fine structure (NEXAFS) spectroscopy.

Assigning a structural motif using spontaneous molecular dipole orientation in thin films

Phys. Chem. Chem. Phys., 2018,20, 29038-29044

Guided by the spontelectric behaviour of thin films of cis-methyl formate, infrared observations and computational investigations reveal the dimer structural motif of the crystalline solid.

Patterned formation of enolate functional groups on the graphene basal plane

Phys. Chem. Chem. Phys., 2018,20, 28370-28374

O atoms selectivley bind at one type of site on the graphene basal plane, creating a long-range patterned distribution of graphene oxide nano-islands.

Enhancing Graphene Protective Coatings by Hydrogen-Induced Chemical Bond Formation

ACS Appl. Nano Mater. 2018, 1, 9, 4509–4515

Increased interactions at the graphene–metal interface yield an effective prevention of intercalation of foreign species below the graphene cover.

Non-linear and non-local behaviour in spontaneously electrical solids

Phys. Chem. Chem. Phys., 2018,20, 5112-5116

We show that solids displaying spontaneous dipole orientation possess quite general non-local and non-linear characteristics expressed through their internal electric fields.

Exciting H2 Molecules for Graphene Functionalization

ACS Nano 2018, 12, 1, 513–520

Hydrogen functionalization of graphene by exposure to vibrationally excited H2 molecules is investigated by combined scanning tunneling microscopy, high-resolution electron energy loss spectroscopy, X-ray photoelectron spectroscopy measurements, and density functional theory calculations.

Public Engagement

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