使用核磁共振(NMR)來研究多孔隙玻璃及人造蛋白石內鎵的熔解與凝固，因鎵被局限於奈米孔隙中，故其熔解點及凝固點皆降低，在升溫的過程中信號強度在 284 K 時開始增加，而在284 K 至 290 K 有明顯的變化，同樣地，在降溫過程裡，信號在280 K 開始降低，且於280 K 和 274 K 之間有顯著的改變，這種在熔解與凝固之間明顯的滯現象顯現出，於多孔玻璃內的鎵不容易形成核種凝固，在升溫過程中71鎵在某些溫度的頻譜中出現兩條譜線，此兩譜線可對應於二液態相。

　　蛋白石中的鎵有很寬的凝固區域，而其熔解的過程則較為急劇，凝固區域從230 K到183 K，熔點則接近245 K，在蛋白石裡的鎵並沒有被觀察到在如多孔玻璃中有超冷的現象，當樣品降溫至 260 K與 210 K之間，出現兩條分別位於122.578 MHz 以及122.571 MHz的譜線，這兩條譜線也可解釋為在蛋白石中存在兩個液態相的證明，它們凝固於不同的溫度區間，但是在同溫度中熔化。

　We use NMR technology to study the melting and freezing processes of gallium in porous glass and opals. Both the melting and freezing points are depressed for confined gallium. In a warming procedure, the integral intensity of 71Ga NMR signal starts to increase at 284 K and changes significantly between 284 and 290 K. Similarly, in a cooling procedure, the intensity of NMR signal starts to decrease at 280 K and changes significantly between 280 and 274 K. The pronounced hysteresis between the melting and the freezing indicates that it is rather difficult for gallium to form enough nuclei to solidify in porous glass. In a warming procedure, some 71Ga NMR spectra have two lines which might correspond to two liquid phases with different melting temperature.

　For gallium in opal, there is a very broad “freezing zone”, but the melting process is much sharper. For an opal with diameter near 250 nm, the “freezing zone” is from 230 to 183 K, and the melting point nears 245 K. Unlike gallium in porous glass, we did not observe supercooling effects for gallium in opal. When the sample is cooling, between 260 and 210 K, the NMR spectra have two resonance lines with frequencies at 122.578 and 122.571 MHz. This behavior can also be interpreted as the existence of two liquid-gallium phases in opal. These two liquid-gallium phases freeze within different temperature areas, but melt at the same temperature.

(1) Christenson, H. K., Confinement effects on freezing and melting, J. Phys.: Condens. Matter 13, R95-R133 (2001).

(2) Michel, D., Borisov, B. F., Charnaya, E. V., Hoffmann, W.-D., Plotnikov P. G. & Kumzerov, Yu A., Solidification and melting of gallium and mercury in porous glasses as studied by NMR and acoustic technique, Nanostruct. Mater. 12, 515-518 (1999)

(3) Tien, C., Wur, C. S., Lin, K. J., Hwang, J. S., Charnaya, E. V. & Kumzerov, Yu A., Properties of gallium in porous glass, Phys. Rev. B 54, 11880 (1996)

(4) Borisov, B. F., Charnaya, E. V., Hoffmann, W. D., Michel, D., Shelyapin, A. V. & Kumzerov, Yu A., Nuclear magnetic resonance and acoustic investigations of the melting-freezing phase transition of gallium in a porous glass, J. Phys.: Condens. Matter 9, 3377-3386 (1997)

(5) Charnaya, E. V., Tien, C., Lin, K. J., and Kumzerov, Yu A., X-ray studies of the melting and freezing phase transitions for gallium in a porous glass, Phys. Rev. B 58 11089 (1998)

(6) Bogomolov, V. N., Kumzerov, Y. A., Romanov, S. G., & Zhuravlev, V. V., Josephson properties of the three-dimension regular lattice of the weakly coupled nanoparticles, Physica C 208, 373 (1993).

(7) Slichter, C. P., Principles of Magnetic Resonance, Third edition, Springer-Verlag New York (1989)

(8) Overloop, K., and L. Van Gerven, Freezing phenomena in adsorbed water as studied by NMR, J. Magn. Reson. A 101 179-187 (1993)

(9) Engemann, S., Reichert, H., Doschert H., Bilgram, J., Honkimäki, V., & Snigirev, A., Interfacial melting of ice contact with SiO2, Phys. Rev. Lett. 92, 205701-4 (2004).

(10) Debenedetti, P. G. and Stanley, H. E., Supercooled and glassy water, Phys. Today 56, 40 (2003).

(11) Poele, P. H., Sciortino, F., Essmann, U., and Stanley, H. E., Phase behaviour of metastable water, Nature (London) 360, 324-328 (1992).

(12) Sastry, S., Debenedetti, P. G., Sciortino, F. and Stanley, H. E., Singularity-free interpretation of the thermodynamics of supercooled water, Phys. Rev. E 53, 6144 (1996).

(13) Elgsaeter, A. & Svare, I., Thermal properties of nickel hexamine salts at the phase transition, J. Phys. Chem. Solids, 31, 1405 (1970)