Importance of convection during physical vapor transport of Hg2Cl2 in the presence of Kr under environments of high gravitational accelerations
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Special attention in the role of convection in vapor crystal growth has been paid since some single crystals under high gravity acceleration of 10g0 appear considerably larger than those under normal gravity acceleration (1g0). With increasing the gravity acceleration from 1g0 up to 10g0, the total molar flux for ΔT = 30 K increases by a factor of 4,while for ΔT = 90, by a factor of 3. The maximum molar fluxes for three different gravity levels of 1g0, 4g0 and 10g0,appear approximately in the neighborhood of y = 0.5 cm, and the molar fluxes show asymmetrical patterns, which indicate the occurrence of either one single or more than one convective cell. As the gravitational level is enhanced form 1g0 up to 10g0, the intensity of convection is increased significantly through the maximum molar fluxes for ΔT = 30 K and 90 K. At 10g0, the maximum total molar flux is nearly invariant for for ΔT = 30 K and 90 K. The total molar flux increases with increasing the gravity acceleration, for 1g0 ≤ gy ≤ 10g0, and decreases with increasing the partial pressure of component B, a noble gas called as Kr (Krypton), PB. The |U|max is directly proportional to the gravity acceleration for 20 Torr PB ≤ 300 Torr. As the partial pressure of PB (Torr) decreases from 300 Torr to 20 Torr, the slopes of the |U|maxs versus the gravity accelerations increase from 0.29 sec to 0.54 sec, i.e. by a factor of 2. The total molar flux of Hg2Cl2 is first order exponentially decayed with increasing the partial pressure of component B, PB (Torr) from 20 Torr up to 300 Torr.
Abstract
Special attention in the role of convection in vapor crystal growth has been paid since some single crystals under high gravity acceleration of 10g0 appear considerably larger than those under normal gravity acceleration (1g0). With increasing the gravity acceleration from 1g0 up to 10g0, the total molar flux for ΔT = 30 K increases by a factor of 4,while for ΔT = 90, by a factor of 3. The maximum molar fluxes for three different gravity levels of 1g0, 4g0 and 10g0,appear approximately in the neighborhood of y = 0.5 cm, and the molar fluxes show asymmetrical patterns, which indicate the occurrence of either one single or more than one convective cell. As the gravitational level is enhanced form 1g0 up to 10g0, the intensity of convection is increased significantly through the maximum molar fluxes for ΔT = 30 K and 90 K. At 10g0, the maximum total molar flux is nearly invariant for for ΔT = 30 K and 90 K. The total molar flux increases with increasing the gravity acceleration, for 1g0 ≤ gy ≤ 10g0, and decreases with increasing the partial pressure of component B, a noble gas called as Kr (Krypton), PB. The |U|max is directly proportional to the gravity acceleration for 20 Torr PB ≤ 300 Torr. As the partial pressure of PB (Torr) decreases from 300 Torr to 20 Torr, the slopes of the |U|maxs versus the gravity accelerations increase from 0.29 sec to 0.54 sec, i.e. by a factor of 2. The total molar flux of Hg2Cl2 is first order exponentially decayed with increasing the partial pressure of component B, PB (Torr) from 20 Torr up to 300 Torr.
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