Giacinto Scoles FRS (2 April 1935 – 24 September 2024) was an Italian-American chemist and physicist who was best known for his pioneering development of molecular beam methods for the study of weak van der Waals forces between atoms, molecules, and surfaces.

There he co-authored one of the first papers on what became soon known as the Senftleben-Beenakker effect:[citation needed] the influence of an external magnetic or electric field on the transport properties of dilute polyatomic gases.

In Genoa he stayed until 1971 and in those years established a renowned molecular beams laboratory devoted to the investigation of intermolecular forces in gases.

Bolometers detect tiny heat input (with noise on the order of 10−14 watts per square root hertz) and had previously been developed as detectors of Infrared Radiation but here they are used to measure the internal and translational energy of a beam of atoms or molecules.

The test apparatus set up together with M. Cavallini and G. Gallinaro[2] offered great advantages with respect to conventional techniques used at that time and reduced the cost of building beam machines.

Scoles performed crossed beam differential scattering cross-section studies of atom-atom, atom-molecule and molecule-molecule interactions,[5] using his bolometer detector.

[10] Brooks Pate brought Scoles and Kevin K. Lehmann together for what proved to be a long series of experiments (and many Ph.D. theses) that characterized Intramolecular Vibrational energy Redistribution.

They first studied the hydrogen stretching fundamental and first overtone spectral regions and observed Lorentzian lineshapes due to irreversible relaxation for large molecules with a very high density of states.

[11] They developed IR-microwave and later IR-IR double resonance methods to provide unambiguous quantum assignments of even highly congested spectra and to reach higher in energy.

In collaboration with Steve Bernasek, Scoles has also studied the influence of vibrational excitation (again for the first time in the first C-H overtone region) on the sticking probability of a molecule (methane) on a metal surface.

Later, Scoles expanded his research into nanoscale biological processes, biophysics, and nanomedicine, in connection with the local Consortium of Molecular Biomedicine.