Adsorbed molecules in external fields: Effect of confining potential

•Spectrum of molecule adsorbed on a surface is evaluated numerically for different types of confining potentials.•Coupling matrix elements of different orders which are required to study such molecules in fields are also calculated.•Response of surface adsorbed molecules to external fields is studied and explained.

We study the rotational excitation of a molecule adsorbed on a surface. As is well known the interaction potential between the surface and the molecule can be modeled in number of ways, depending on the molecular structure and the geometry under which the molecule is being adsorbed by the surface. We explore the effect of change of confining potential on the excitation, which is largely controlled by the static electric fields and continuous wave laser fields. We focus on dipolar molecules and hence we restrict ourselves to the first order interaction in field-molecule interaction potential either through permanent dipole moment or/and the molecular polarizability parameter. It is shown that confining potential shapes, strength of the confinement, strongly affect the excitation. We compare our results for different confining potentials.

Graphical abstractThe figure shows the variation of energy eigenvalues for lowest eight states of confined rotor with static electric field (γ = μ Es/Be) without external laser field (η = 0) (a,c,e,g) and with the laser field (η = 100) (b,d,f, and h). All relevant quantities are represented in units of Be (the rotational constant of the molecule).Figure optionsDownload full-size imageDownload as PowerPoint slide