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20年反差:《中国科学》VS《物理学报》
1988年,《中国科学》发表了一篇文章,题目为“由Nd2Fe14B的晶体结构直接给出其价电子结构的分析”,作者为张瑞林(吉林大学),吴尚才(广州有色金属研究所),余瑞璜(吉林大学),文章篇幅为7页。
文章没有任何科研项目的标注(可能没有得道资助)。原文下载:《中国科学》文章
20年后的2008年,《物理学报》也发表了一篇文章,题目为“Nd2Fe14B的价电子结构分析和磁性计算”,作者为吴文霞,郭永权,李安华,李卫(钢铁研究总院功能材料研究所),文章篇幅为7页,文章下面的标注是:国家高技术研究发展计划(批准号:2007AA03Z458) ;北京市科技研究计划重大项目(批准号:D0406002000091) 。
原文下载:《物理学报》文章
20年的反差是:科研经费发生了翻天覆地的变化,文章的德性却是在向下滑。经费的数额是大大地上去了,但是文章的德性却是下来了。
无论读者(网友)是否为当事人,先不要激动,文章的事情是白纸黑字,谁也无法销毁证据,再说,俺是绝对地用数据说话的,评论的误差精确到0.005埃。
《物理学报》的文章,最基本的数据和图表都是从一篇文献(Herbst J F 1991 Rev. Mod. Phys. 63 822)抄引来的,文献题目为R2Fe14B Materials: Intrinsic properties and technological aspects,篇幅为85页。
原文下载:Rev. Mod. Phys文章(压缩后16M,无法上传)
《物理学报》文章的表1(没有标注):
参考文献Rev. Mod. Phys.的表1:
需要提醒的是,Fe(4e)的坐标是一种不规范的写法,因为其他原子的坐标都按照国际空间群表(136号空间群)的规范书写,而Fe(4e)却是例外,标准的格式应该书写为(0,0,0.614),或者是(0,0,-0.386)。
余瑞璜先生(第一作者为张瑞林)的文章先是把(0.5,0.5,0.114)解读为(0,0,0.114),然后代入键距公式计算,得到第一条键的键距d=1.6411【(4e-Fe)-(8j-1-Fe),d=1.6411】,两个Fe原子的距离几乎等于Fe原子的半径,这是绝对不可能的。因此,余瑞璜先生把(0,0,0.114)修改为(0,0,0.386)后,得到的第一键距为d(Fe-B)=2.0975。
《中国科学》的文章表述如下:
毫无疑问,余瑞璜先生把4e-Fe原子的坐标弄错了,由此产生的后果是,原子间距小于4.0000埃的全部实验键距有55条,也不是余瑞璜先生所说的44条。根据俺的《点群/空间群操作系统》计算表明,55条键中,有些键是无法求解出等效数目的,因为数据发生了紊乱,破坏了数据的对称性。
由于4e-Fe原子坐标的错误,计算出的键络已经不是严格意义的Nd2Fe14B了,究竟对电子结构有多大的影响,这需要定量评估,俺现在没有时间做这些事情。
下载:错误的键参数数据
应用经验电子理论的难点是求解各种原子间距和配位数,事实表明,连EET创始人余瑞璜先生都出错,别人出错就更容易了。实际上这也是评估EET电子理论的难点,因为从一开始就错了,而且是错在对晶体结构的把握上,因为还没有进入到EET的计算就错了,因此,文章的结论和EET本身似乎没有什么关系。
余瑞璜先生是中国少有的系统地建立了自己理论的科学家,俺始终认为EET理论是非常地撩人心弦的,可惜很多文章的计算还没有进入到EET本身就开始出错了,这种由于对晶体学基础知识的理解所导致的错误,是不应该记在EET理论的头上。
余瑞璜先生是中国少有的晶体学家,早年师从大科学家布拉格(晶体x射线衍射诺贝尔奖)。
余瑞璜先生的EET理论,要求我们从崭新的角度来看待晶体学的基础知识,但是那些鼠目寸光的基金评审专家却自欺欺人地说,晶体学的几何问题都已经解决了,再没有研究的必要了。
余瑞璜先生EET理论得不到实质性的发展,完全是受制于人们对晶体结构基础性知识的理解和把握。
但是,无论如何,《中国科学》文章的键距和配位数是余瑞璜等人自己亲自计算的,可惜没有算对。
20年后,《物理学报》的文章对Nd2Fe14B的电子结构进行了类似的计算。他们所使用的原始数据和余瑞璜所使用的原始数据是完全相同的(来自同一篇文献),但是得到的键距和配位数等数据却是完全不同的。
《物理学报》文章的作者声称他们自己亲自进行了计算,原文如下:
《物理学报》文章的作者所说的“结构参数(空间群、点阵常数和原子占位)”,就是他们列出的表1的数据,可是他们并没有使用所谓的Diamond 软件根据表1的数据去计算(测量)键距和原子配位数。
为什么这么说呢?
下载:文献(1991 Rev. Mod. Phys. 63 822) (压缩后16M,无法上传)
因为文献(1991 Rev. Mod. Phys. 63 822)里有一个表2,给出了所有小于4.000埃原子间距和(配对)配位数,如下所示。
表里共列出42条键(注意有相同的),《物理学报》的文章抄引时漏掉了d=2.6351埃这条,结果变成了41条,如下表所示。
如果《物理学报》的文章根据表1的原始数据进行计算,得到的结果应该和文献里 Table 2 的数据是有差别的,不少键可以反映在键长的最后一位。
如果《物理学报》文章的作者自己计算键距和配位数的话,就可以发现《中国科学》文章的错误。但是,由于那数据是抄引来的,而不是自己计算的,因此,多一事不如少一事。
如果把《中国科学》和《物理学报》的两篇文章放在一起来阅读,客观上给读者的印象是:EET电子理论的键参数(键数目,键长和配位数或者叫等同键数目)是随意的。
这实际上是败坏了EET电子理论的名声。
《物理学报》文章里还有一个Nd2Fe14B的晶体结构图,和文献(1991 Rev. Mod. Phys. 63 822)里的一模一样。这些与EET理论没有关系,就不多说了。
最后一个问题,文献(1991 Rev. Mod. Phys. 63 822)里的键距和配位数是不是完全正确呢?
作者Herbst J F给出的原子间距和(配对)配位数是完全正确的。
本博主检验了 Table 2 的每一个数据,结果如下:
如果把42条键的数据按照原子来分拣,就得到了 Table 2 的结果。
以 Nd(f)原子为中心的各种键和配位原子(程序输出数据):
下面有蓝颜色字段解释说明。
23," ","8j-2-Fe","---","4f-Nd"," d===",3.0625
"8j-2-Fe",":",1.6104,1.6104,9.1012," Z=",1
" SP coordinates=",.683,.683,1.246
" 配位原子:","4f-Nd",": ",2.0416,2.0416,6.1
" SP coordinates=",.732,.732,1
"4f-Nd",":",2.0416,2.0416,6.1," Z=",6
" SP coordinates=",.732,.732,1
" 配位原子:","16k-2-Fe",": ",1.232,4.0744,3.9528
" SP coordinates=",.64,.963,.824
" 配位原子:","16k-2-Fe",": ",1.232,4.0744,8.2472
" SP coordinates=",.64,.963,1.176
" 配位原子:","8j-2-Fe",": ",1.6104,1.6104,3.0988
" SP coordinates=",.683,.683,.754
" 配位原子:","8j-2-Fe",": ",1.6104,1.6104,9.1012
" SP coordinates=",.683,.683,1.246
" 配位原子:","16k-2-Fe",": ",4.0744,1.232,3.9528
" SP coordinates=",.963,.64,.824
" 配位原子:","16k-2-Fe",": ",4.0744,1.232,8.2472
" SP coordinates=",.963,.64,1.176
需要强调的是,本博主给出的配位数是空间配位数,Table 2 给出的Neighbors是配对配位数。
例如,围绕4f-Nd原子有6个原子:4个16k-2-Fe原子,2个8j-2-Fe原子。
因为现在讨论的键是8j-2-Fe---4f-Nd,只考虑围绕4f-Nd的8j-2-Fe原子,而不考虑16k-2-Fe原子。
因此,4f-Nd的(配对)配位原子是2个。
4f-Nd原子和16k-2-Fe原子的距离也为d=3.0625,这是下面的键。
对于键4f-Nd---16k-2-Fe,围绕4f-Nd原子有4个16k-2-Fe原子,这就是为什么Table 2 要写成:
Nd(f) --------- 4Fe(k2) d=3.06 (d=3.0656-0.005=3.06)
--------- 2Fe(j2) d=3.07 (d=3.0625+0.005=3.07)
注意,俺的程序判断键的误差为±0.005埃。
但是,一条键是由什么原子组成的,周围的空间配位数是多少,这是绝对不能含糊的。
围绕4f-Nd组成的键(键长小于4.000埃)共有8条,数据如下,解读方法同上。
24," ","4f-Nd","---","16k-2-Fe"," d===",3.0656
"4f-Nd",":",-10.8416,-10.8416,-6.1," Z=",6
" SP coordinates=",-.732,-.732,0
" 配位原子:","16k-2-Fe",": ",-12.8744,-10.032,-8.2472
" SP coordinates=",-.963,-.64,-.176
" 配位原子:","16k-2-Fe",": ",-12.8744,-10.032,-3.9528
" SP coordinates=",-.963,-.64,.176
" 配位原子:","8j-2-Fe",": ",-10.4104,-10.4104,-9.1012
" SP coordinates=",-.683,-.683,-.246
" 配位原子:","8j-2-Fe",": ",-10.4104,-10.4104,-3.0988
" SP coordinates=",-.683,-.683,.246
" 配位原子:","16k-2-Fe",": ",-10.032,-12.8744,-8.2472
" SP coordinates=",-.64,-.963,-.176
" 配位原子:","16k-2-Fe",": ",-10.032,-12.8744,-3.9528
" SP coordinates=",-.64,-.963,.176
"16k-2-Fe",":",-10.032,-12.8744,-8.2472," Z=",1
" SP coordinates=",-.64,-.963,-.176
" 配位原子:","4f-Nd",": ",-10.8416,-10.8416,-6.1
" SP coordinates=",-.732,-.732,0
25," ","16k-1-Fe","---","4f-Nd"," d===",3.0791
"16k-1-Fe",":",6.3624,.5896,16.7506," Z=",1
" SP coordinates=",1.223,.567,1.873
" 配位原子:","4f-Nd",": ",6.7584,-2.0416,18.3
" SP coordinates=",1.268,.268,2
"4f-Nd",":",6.7584,-2.0416,18.3," Z=",4
" SP coordinates=",1.268,.268,2
" 配位原子:","16k-1-Fe",": ",6.3624,.5896,16.7506
" SP coordinates=",1.223,.567,1.873
" 配位原子:","16k-1-Fe",": ",6.3624,.5896,19.8494
" SP coordinates=",1.223,.567,2.127
" 配位原子:","16k-1-Fe",": ",9.3896,-2.4376,16.7506
" SP coordinates=",1.567,.223,1.873
" 配位原子:","16k-1-Fe",": ",9.3896,-2.4376,19.8494
" SP coordinates=",1.567,.223,2.127
28," ","4c-Fe","---","4f-Nd"," d===",3.1193
"4c-Fe",":",0,4.4,6.1," Z=",2
" SP coordinates=",.5,1,1
" 配位原子:","4f-Nd",": ",-2.0416,6.7584,6.1
" SP coordinates=",.268,1.268,1
" 配位原子:","4f-Nd",": ",2.0416,2.0416,6.1
" SP coordinates=",.732,.732,1
"4f-Nd",":",2.0416,2.0416,6.1," Z=",2
" SP coordinates=",.732,.732,1
" 配位原子:","4c-Fe",": ",0,4.4,6.1
" SP coordinates=",.5,1,1
" 配位原子:","4c-Fe",": ",4.4,0,6.1
" SP coordinates=",1,.5,1
30," ","4e-Fe","---","4f-Nd"," d===",3.2048
"4e-Fe",":",8.8,0,-4.7092," Z=",2
" SP coordinates=",1.5,.5,.114
" 配位原子:","4f-Nd",": ",6.7584,-2.0416,-6.1
" SP coordinates=",1.268,.268,0
" 配位原子:","4f-Nd",": ",10.8416,2.0416,-6.1
" SP coordinates=",1.732,.732,0
"4f-Nd",":",10.8416,2.0416,-6.1," Z=",2
" SP coordinates=",1.732,.732,0
" 配位原子:","4e-Fe",": ",8.8,0,-7.4908
" SP coordinates=",1.5,.5,-.114
" 配位原子:","4e-Fe",": ",8.8,0,-4.7092
" SP coordinates=",1.5,.5,.114
32," ","4f-Nd","---","8j-1-Fe"," d===",3.2665
"4f-Nd",":",-11.1584,11.1584,-12.2," Z=",2
" SP coordinates=",-.768,1.768,-.5
" 配位原子:","8j-1-Fe",": ",-9.6624,9.6624,-14.6888
" SP coordinates=",-.598,1.598,-.704
" 配位原子:","8j-1-Fe",": ",-9.6624,9.6624,-9.7112
" SP coordinates=",-.598,1.598,-.296
"8j-1-Fe",":",-9.6624,9.6624,-9.7112," Z=",1
" SP coordinates=",-.598,1.598,-.296
" 配位原子:","4f-Nd",": ",-11.1584,11.1584,-12.2
" SP coordinates=",-.768,1.768,-.5
35," ","4g-B","---","4f-Nd"," d===",3.3036
"4g-B",":",1.1352,-9.9352,6.1," Z=",2
" SP coordinates=",.629,-.629,1
" 配位原子:","4f-Nd",": ",-2.0416,-10.8416,6.1
" SP coordinates=",.268,-.732,1
" 配位原子:","4f-Nd",": ",2.0416,-6.7584,6.1
" SP coordinates=",.732,-.268,1
"4f-Nd",":",2.0416,-6.7584,6.1," Z=",2
" SP coordinates=",.732,-.268,1
" 配位原子:","4g-B",": ",-1.1352,-7.6648,6.1
" SP coordinates=",.371,-.371,1
" 配位原子:","4g-B",": ",1.1352,-9.9352,6.1
" SP coordinates=",.629,-.629,1
40," ","4f-Nd","---","4g-Nd"," d===",3.7629
"4f-Nd",":",-2.3584,11.1584,0," Z=",2
" SP coordinates=",.232,1.768,.5
" 配位原子:","4g-Nd",": ",-1.232,7.568,0
" SP coordinates=",.36,1.36,.5
" 配位原子:","4g-Nd",": ",1.232,10.032,0
" SP coordinates=",.64,1.64,.5
"4g-Nd",":",-1.232,7.568,0," Z=",2
" SP coordinates=",.36,1.36,.5
" 配位原子:","4f-Nd",": ",-2.3584,11.1584,0
" SP coordinates=",.232,1.768,.5
" 配位原子:","4f-Nd",": ",2.3584,6.4416,0
" SP coordinates=",.768,1.232,.5
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