title: Direct determination of the sign of the NO dipole moment.
abstract: We report a novel approach for determining the sign of permanent dipole moments, using nitric oxide [NO(v=0)] as an example. State-selected NO (j=|m|=|Omega=1/2) molecules are focused using a hexapole and oriented in a strong dc electric field. The angular distributions of ionic fragments resulting from extreme ultraviolet single-photon and multiphoton dissociative ionization at 400 and 800 nm are measured and indicate that the dipole moment is negative (corresponding to N-O+). The experiments thus rule out an error in the sign of the dipole of NO as the possible source of a remarkable discrepancy between previous theoretical and experimental work on orientation effects in bimolecular collisions involving oriented NO.
authors.affiliation: FOM Institute for Atomic and Molecular Physics (AMOLF), Kruislaan 407, 1098 SJ Amsterdam, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Gijsbertsen
authors.forename: W
authors.initials: W
authors.lastname: Siu
authors.forename: M F
authors.initials: MF
authors.lastname: Kling
authors.forename: P
authors.initials: P
authors.lastname: Johnsson
authors.forename: P
authors.initials: P
authors.lastname: Jansen
authors.forename: S
authors.initials: S
authors.lastname: Stolte
authors.forename: M J J
authors.initials: MJ
authors.lastname: Vrakking