title: Spectroscopy challenge 9.
authors.affiliation: Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040, Madrid, Spain. rma@quim.ucm.es
authors.forename: Roberto
authors.initials: R
authors.lastname: Martínez-Alvarez
authors.forename: Antonio
authors.initials: A
authors.lastname: Herrera
authors.forename: Pedro
authors.initials: P
authors.lastname: Ramiro