Can prolonged exposure to highly intense infrared light cause electrons to be ejected from a clean metal surface

No

Explanation:

In order to cause electrons to be ejected from a clean metal surface, ultraviolet radiation must be used.

This effect is known as photoelectric effect: when electromagnetic radiation with a certain frequency hit the surface of a metal, electrons are extracted from the metal. However, the radiation that hits the metal must have energy above a certain threshold, which is called 'work function' of the metal. The work function for most metals corresponds to the energy carried by photons with frequency in the ultraviolet range. Remember that the energy carried by a photon is given by

where h is the Planck constant and f is the frequency: therefore, energy is proportional to the frequency. Ultraviolet photons have greater frequency than infrared photons, so ultraviolet photons have enough energy to extract the photoelectrons from the metal, while infrared photons do not. It does not matter if the exposure is prolonged: if the frequency of the incident radiation is below the threshold frequency (which corresponds to the work function), then no electrons can be extracted.