In the past dozens of years

with the development of magneto-optical technology

the properties of the polaron in a magnetic field have been widely studied both experimentally and theoretically. However

the properties of magnetopolaron have not been investigated by Huybrechts method so far. The excitation energy of the strong coupling surface polaron have been calculated using Huybrechts method by the present authors and co-workers. The properties of the surface magnetopolaron in polar crystals were studied. The ground state vibration frequency and the effective Hamiltonian of surface magnetopolaron were derived by using the linear combination operator and the unitary transformation method. Two limiting cases of the coordinate z for the electron-SO phonon and electron-LO phonon system are discussed. Numerical calculations

for the RbCl crystal as an example

are performed. We find that due to the existence of the surface optical (SO) phonons

the electrons move more close to the surface

the interactions between the electrons and the SO phonons become more strong. When the electron infinitely close to the surface

the contribution of the LO phonon can be neglected. On the other hand

the contribution of the bulk LO phonon will increase with the increase of the distance between electron and the surface. At this moment

the contribution of the bulk LO phonon is much greater than SO phonon's

and then we can omit the SO phonon. The results show that the vibration frequency and the parallel effective Hamiltonian of surface magnetopolaron will be increased with increasing magnetic field. The reason is that with the increase of magnetic field the location of the magnetopolaron will be enhanced.