SOURCE-ENHANCED CONDENSATION IN MONOCOMPONENT DISPERSE SYSTEMS

Homogeneous condensation in the presence of a spatially uniform source producing a condensible monocomponent substance is considered within the model assuming the condensation growth to follow the scheme (g)+(1)-->(g+1), with g being the number of monomers (molecules of the condensing substance) in the growing particle. The mass spectrum is expressed in terms of the function describing time evolution of the monomer concentration. In contrast to the case of free condensation (no external source) the mass spectrum is a smooth function of the particle mass with the frontal peak moving with time to the right along the mass axis. The particle number concentration is shown to either grow unlimitedly with increasing time or remain finite, depending on how fast the condensation coefficients alpha(g) describing the rates for monomer accretion grow with the particle mass g. For power dependencies alpha(g) (proportional to)g(lambda), the condensation regime changes at lambda = 1/2. The analogy of this phenomenon with the second order phase transitions is marked. Numerical calculations for powerlike alpha(g) at lambda = 0, 1/3 1/2, 2/3, and 1 illustrate the characteristic features of the mass spectra in source-enhanced condensing systems. The cases lambda = 0 and lambda = 1 are treated analytically.