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Study of the dynamic behavior of liquid Oxygen under high magnetic field

强磁场下液氧动态行为研究

基本信息

批准号：
62460036
负责人：
YAMAGISHI Akio
金额：
$ 4.16万
依托单位：
The Research Center for Extreme Materials, Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1988
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-62460036/
关键词：
liquid oxygen two-molecule transition high magnetic field magneto-volume effect superconducting magnet paramagnetic liquid liquid surface magnetic fluid 磁気流体脱色磁気褪色効果磁歪

项目摘要

In this research program, we aided to analyze theoretically and experimentally the dynamic behavior of liquid oxygen under high magnetic field and visually observe the phenomena.Oxygen is ideal paramagnetic liquid so that it was expected to behave differently under strong magnetic field. We found mainly three magnetic effects: 1) faint blue color of liquid oxygen fades out nonlinearly with applied field intensity, 2) liquid oxygen expands with magnetic field and 3) liquid surface takes sharp cone shape under strong magnetic field.The absorption of 633 and 577 nm light, shich is a cause of blue color, is due to two molecule transitions ^3sigma_g ^3sigma_g-^1delta_g ^1delta_g. From spin conservation before and agter the transition, the total spin moment of the ground state should be zero. However under an applied magnetic gield, each spins are oriented in the field direction so that the total spin has non-zero value and the transition would be inhibited. This is the outline of the "blue color disappearance". We found "spin-pair model" for liquid oxygen which explains the above phenomenon well. Essential point is that distance of two oxygen molecules interacting is fairly short compared with the other molecules surrounding them and the two molecules makes new states with two spins S=1.Two oxygen molecules are coupled with antiferromagnetic interaction so that repulsive force elongates the molecular distance when two spins are oriented by magnetic field. This is the origin of the magneto-volume effect. 0.2% increase of volume is observed with 8 T mabnetic field.The surface shape is determined to have minimum energy. Surface cone shape is due to the balance of surface tension, gravity force and magnetic force. The changing of the surface shape is recorded in video-recorder and photo-pictures.

在本研究项目中，我们从理论上和实验上分析了液氧在强磁场下的动力学行为，并对现象进行了直观的观察。氧是理想的顺磁性液体，因此在强磁场下，它的行为会有所不同。我们主要发现了三种磁效应：1)液氧的淡蓝色随外加磁场强度非线性地逐渐消失，2)液氧随磁场的增大而膨胀，3)在强磁场下液氧表面呈尖锥状。633 nm和577 nm光的吸收是蓝色的一个原因，这是由于两个分子跃迁^3sigma_g ^3sigma_g-^1delta_g ^1delta_g。从跃迁前后的自旋守恒来看，基态的总自旋矩应为零。但在外加磁场作用下，由于各自旋方向与磁场方向一致，使得总自旋具有非零值，跃迁受到抑制。这就是“蓝色消失”的轮廓。我们建立了液态氧的“自旋对模型”，很好地解释了上述现象。关键是两个氧分子相互作用的距离与周围的其他分子相比是相当短的，两个分子形成两个自旋为S=1的新态。两个氧分子与反铁磁相互作用耦合，当两个自旋被磁场定向时，斥力延长了分子距离。这就是磁体积效应的起源。在8t磁场下，体积增大0.2%。表面形状被确定为具有最小能量。表面的锥体形状是由于表面张力、重力和磁力的平衡。用摄像机和照片记录了表面形状的变化。