Encounters between a 1.4 M. neutron star and a 0.8 M. red giant and main-sequence star are simulated using a three-dimensional smoothed particle hydrodynamics (SPH) code. The rcd giant is modeled as a massive core surrounded by a gaseous envelope, while the main-sequence star is modeled as a polytrope of index n = 1.5. The neutron star is treated as a single particle. Encounters at various impact parameters and with relative velocities pertinent to globular clusters (10 km s-1) are studied. In the case of encounters involving a red giant, bound systems are produced when the separation at periastron passage R(MIN) less than or similar to 2.5R(RG). The effect of the encounter depends strongly on the impact parameter. For close encounters and physical collisions, a common envelope system is produced. After the envelope of gas has been removed, a tight binary comprising of a white dwarf (previously the red giant core) and the neutron star remains. The two stars will spiral toward each other, due to the emission of gravitational radiation, such that the white dwarf will fill its Roche lobe in less than a Hubble time. For more distant encounters (i.e., 1.8R(RG) less than or similar to R(MIN) less than or similar to 2.5R(RG)), a detached binary may be produced that will form an LMXB when the red giant further evolves and fills its Roche lobe. After mass transfer has ceased, such binaries will contain a millisecond pulsar (MSP). For main-sequence stars, an encounter with a neutron star will produce one of two distinct objects: close encounters and physical collisions (i.e., R(MIN) less than or similar to 1.75R(MS)) leave a single object with the neutron star engulfed in a thick disk while the rest of the encounters that produce bound systems (i.e., 1.75R(MS) less than or similar to R(MIN) less than or similar to 3.5R(MS)) may form detached binaries that later pass through an LMXB phase before, presumedly, producing a binary containing an MSP. The subsequent evolution of the thick disk systems is currently unclear. Possibly enough of the material will be accreted by the neutron star to produce a lone MSP. However, even if all these systems do produce MSPs, we still only obtain a factor of 2 increase in the expected ratio of MSPs to LMXBs, which is insufficient to have the standard model (where MSPs are produced from LMXBs) comply with observations.
