Mass-to-charge ratio used as its unit in the field of mass spectrometry. Some fields use the charge-to-mass ratio ("Q"/"m") instead, which is the multiplicative inverse of the mass-to-charge ratio. The 2014 CODATA recommended value for an electron is = . When charged particles move in electric and magnetic fields the following two laws apply: where F is the force applied to the ion, "m" is the mass of the particle, a is the acceleration, "Q" is the electric charge, E is the electric field, and v × B is the cross product of the ion's velocity and the magnetic flux density. This
Drude particle a changing local environment. Classical Drude particles are massless virtual sites carrying a partial electric charge, attached to individual atoms via a harmonic spring. The spring constant and relative partial charges on the atom and associated Drude particle determine its response to the local electrostatic field, serving as a proxy for the changing distribution of the electronic charge of the atom or molecule. However, this response is limited to a changing dipole moment. This response is not enough to model interactions in environments with large field gradients, which interact with higher order moments. The major computational cost of simulating classical