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&&【求助】IR spectrum分析
【求助】IR spectrum分析
下面是我计算的IR spectrum，但不知道怎么分析，& &从上面能得到LO-TO的频率吗？怎么区分？请高手指点，谢谢！& && && && &
&&Vibrational Frequencies& && && && && && && && &&&
& && && && && && && && && & -----------------------& && && && && && && && &&&
& && && && && && && && && && && && && && && && && && && && && && && && && &
&&Performing frequency calculation at&&1 wavevector&&(q-pt )& && && && && &&&
& && && && && && && && && && && && && && && && && && && && && && && && && &&&
+ --------------------------------------------------------------------------
+&&q-pt=& & 1 (&&0...000000)& &&&1.000000& && && && && && &
+ --------------------------------------------------------------------------
+& &&&N& && &Frequency irrep.& & ir intensity active& && && && &raman active +
+& && && && && & (cm-1)& && && &((D/A)**2/amu)& && && && && && && && && && &&&
+& && && && && && && && && && && && && && && && && && && && && && && && && &
+& &&&1& &&&-15.202437& &a& && && & 0.0000000&&N& && && && && && && &&&N& &&&+
+& &&&2& &&&-15.202437& &a& && && & 0.0000000&&N& && && && && && && &&&N& &&&+
+& &&&3& &&&-15.202437& &a& && && & 0.0000000&&N& && && && && && && &&&N& &&&+
+& &&&4& && &42.741400& &a& && && &68.1876222&&Y& && && && && && && &&&N& &&&+
+& &&&5& && &42.741400& &a& && && &68.1876222&&Y& && && && && && && &&&N& &&&+
+& &&&6& && &42.741400& &a& && && &68.1876222&&Y& && && && && && && &&&N& &&&+
+& &&&7& &&&147.155697& &a& && && & 4.3908011&&Y& && && && && && && &&&N& &&&+
+& &&&8& &&&147.155697& &a& && && & 4.3908011&&Y& && && && && && && &&&N& &&&+
+& &&&9& &&&147.155697& &a& && && & 4.3908011&&Y& && && && && && && &&&N& &&&+
+& & 10& &&&234.606105& &b& && && & 0.0000000&&N& && && && && && && &&&N& &&&+
+& & 11& &&&234.606105& &b& && && & 0.0000000&&N& && && && && && && &&&N& &&&+
+& & 12& &&&234.606105& &b& && && & 0.0000000&&N& && && && && && && &&&N& &&&+
+& & 13& &&&462.532793& &a& && && & 9.0242227&&Y& && && && && && && &&&N& &&&+
+& & 14& &&&462.532793& &a& && && & 9.0242227&&Y& && && && && && && &&&N& &&&+
+& & 15& &&&462.532793& &a& && && & 9.0242227&&Y& && && && && && && &&&N& &&&+
+ ..........................................................................
+& && &&&Character table from group theory analysis of eigenvectors& && && &
+ ..........................................................................
+ Rep Mul |& &E& &2& &3& &2& &4& &I& &m&&-3& &m&&-4& && && && && && && && &&&
+& && && &|----------------------------------------& && && && && && && && &&&
+& &a& &4 |& &3&&-1& &0&&-1& &1&&-3& &1& &0& &1&&-1& && && && && && && && &&&
+& &b& &1 |& &3&&-1& &0& &1&&-1&&-3& &1& &0&&-1& &1
请教一下；）
我所知道的计算晶体振动频率的只有两种方法，一个叫做什么冻结原子法，另一个就是线性响应。您说的有限差分是那个所谓的冻结原子法么？
为什么有限差分无法计算LOTO劈裂？
另：MS4.1的castep可以计算声子谱，包括不理园区非特殊点。我很久没用了，应该是线性响应的方法；）
计算gama点声子谱，加入LOTO劈裂参数
在计算结构中找到振动模式，用图形软件画图
另：你的虚频是15个波数，而最低光学模在40个波数，差别太小。你最好设法将gama点的声学模调到更接近0，否则时，可能会有麻烦
是冻结原子法，又叫直接法，具体原因网上有：
直接法，或称frozen-phonon方法，是通过在优化后的平衡结构中引入原子位移，计算作用在原子上的Hellmann-Feynman力，进而由动力学矩阵算出声子色散曲线。用该方法计算声子色散曲线最早开始于80年代初。由于计算简便，不需要特别编写的计算程序，很多小组都采用直接法计算材料性质。直接法的缺陷在于它要求声子波矢与原胞边界(super size)正交，或者原胞足够大使得Hellmann-Feynman力在原胞外可以忽略不计。这使得对于复杂系统，如对称性高的晶体、合金、超晶格等材料需要采用超原胞。超原胞的采用使计算量急剧增加，极大的限制了该方法的使用。这种方法不能很好的预言LO-TO splitting,只有在计算了Born effective charge和dielectric constant之后，进一步考虑了 non-analyticity term，才能计算出;但Direct Method本身并不能给出Born effective charge和dielectric constant.所以这也是它的一个缺陷.，
谢谢你的指点；）
LOTO劈裂来源于长程库伦力，而frozen方法中无法给出这一相互作用：）
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【求助】请问什么是HSQC spectrum？这个怎么用？
请问什么是HSQC spectrum？这个怎么用？用来表征什么？
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Data Acquisition
Spectrum Analyser - iOS
Spectrum Analyzer
Simple and Intuitive
WiPry-Spectrum is the first 2.4GHz ISM band spectrum analyzer designed specifically for the iPhone, iPod touch, and iPad. It is simple and intuitive to use. It allows you to &Pry& into your WiFi environment to detect and avoid noisy channels. Download WiPry in the App Store and test drive our interface for free.
Product Specs
Frequency Range: 2.4-2.495GHz
Antenna: External with SMB
Amplitude Range: -40dBm to 20dBm
Amplitude Resolution: 2.0dBm
Resolution Bandwidth: 1MHz
Sweep Time: 200ms
How To Transform an iPhone into a 2.4GHz Spectrum Analyzer
&Visualization Tools: Everything You Need
The visualization techniques used in WiPry-Spectrum give you the ability to see your wireless network from a variety of different perspectives. Some prefer the real wave view (top left), and some prefer waterfall mode (top right). Regardless of your preference, we have all the tools that you need to identify and avoid interference.
&Identify and Avoid Interference By Changing Channels
The 2.4GHz band is a busy place. Your wireless internet operates in this range, as well as other electronic devices such as baby monitors, cordless phones, garage door openers, and microwave ovens. Since WiFi can extend as far as a football field, nearby buildings or residences can also cause interference. This activity is organized into channels. WiPry-Spectrum allows you to see exactly where noise is coming from along the &spectrum& so that you know which channels to avoid. In the example above, you would avoid channel 3 (along with any overlapping channels) because it has the most noise. Then, you would select channel 10 (or another channel without interference). Now you can answer the question: which channel should my wireless network use?
WiPry-Spectrum
Product Specs
Frequency Range: & & & &2.4-2.495 GHz &&
Antenna: & & & & & & & & &External with SMB
Amplitude Range: &-40dBm to 20dBm
Amplitude Resolution: & & & & & & &2.0dBm
Resolution Bandwidth: & & & & & & & &1MHz
Sweep Time: & & & & & & & & & & & & & & 200ms
Buy WiPry-Spectrum Online:
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WiPry-Spectrum can help you optimize your network settings. It can also help you identify rogue access points and polluters on the 2.4GHz ISM band.
WiPry-Spectrum will allow you to view which frequencies in the spectrum are already in use or have a high noise floor. Selecting a channel with a low reading will yield increased throughput and lower latency.&
For specific frequency measurements, you can use the cursors or the divisions on the screen. To view WiFi channels, click on the plus sign in the top left corner. Then, tap on any of the channel numbers listed. It is also possible to enable specific WiFi guides such as 802.11b, 802.11g, 802.11n -20MHz (2.4GHz only). To change the channel map, go to the menu bar and tap Measure. The option at the bottom of the menu is WiFi guide. This will enable you to manually select a guide. The default is 802.11n - 20MHz.
Yes, you do need to install the app, WiPry. &The app is easy to install and available for free in the Apple App Store.
The gain of the supplied antenna is 1dBi.
The center frequency of the supplied antenna is 2.45GHz.
Yes. It is also possible to email the screenshot directly from your device.
Yes. Touch and hold the pause / play menu icon and it will change into single shot mode. After the mode has been changed, tap the single shot icon and the next event will be captured and held. To go back to pause / play mode, touch and hold the single shot icon.
No. WiPry-Spectrum was designed for WiFi and 2.4GHz applications.
No, it is not. The RF span is 2.4-2.495GHz.
We have included internal attenuation in the design of WiPry so that you can look at higher power signals without damaging the detectors.
20dBm is the max. If you need to make higher power measurements, please make sure that you use external attenuation to bring the power level below 20dBm.
External attenuation allows you to apply an offset (either gain or attenuation) to bring the measurement into range.
You will need the conducted measurement kit even if you still plan to make radiated measurements.
There are many manufacturers of attenuators. Google 'RF Attenuators' for a large listing.&
We will make attenuators if the demand is large enough. Please drop us a note if you are interested.
If you're using an iPhone / iPod touch, you can use WiPry-Spectrum continuously for approximately five hours.&
If you're using an iPad, you can use WiPry-Spectrum continuously for approximately eight hours.
Please understand that these estimates are just that, estimates. Your results may vary based on your background usage level (WiFi, email push, other apps, etc).
Yes, WiPry-Spectrum comes with a one year warranty.
WiPry-Spectrum works on all generations of the iPod Touch, iPhone, and iPad devices running iOS version 3.1.3 or higher. It is made for:
iPod touch (1st, 2nd, 3rd&and 4th&generation)
iPhone 5 (al models)
iPhone 3GS就酱，这款APP让手机也能变成色温表！
今天，介绍的LightSpectrum Pro是一个非常实用的iOS APP，能够将你的iPhone变成一个色温表！之前我们推送过关于Log的APP介绍，看着自己的手机变得越来越强大，是不是感觉摄影越来越容易和方便了。
不幸的是，LightSpectrum Pro并不是一个免费的iOS APP，约合人民币13块钱。不过，相对于一个专业的测光表来说，这个钱就是连零头都不够，绝对值得买来一试。当然，两者的功能和准确性绝对不能相提并论，但LightSpectrum Pro的确能够提供基本的色温信息，并在摄影时有一定的帮助。
LightSpectrum Pro的使用方法很简单，只需要使用手机的前/后镜头构图，它便会分析画面出现的光线色彩，然后便会推断出画面当时的色温值。
换句话，LightSpectrum Pro是反射式的设计，而非正规色温表入射式的设计。入射式色温表只需要将仪器对向光源变可以得出准确的色温。
而反射式色温表使用时则需对着拍摄的主体，但这不是一个准确的测色温方法，因为画面中的颜色会干扰色温表分析结果。试想想，如果画面中出现一大片黄色，色温表变以为现场的光线很黄，因而错误判断出现场色温很低。
所以，千万别期望使用LightSpectrum Pro得出色温，然后更改相机的白平衡来获取更准确的白平衡，因为LightSpectrum Pro的工作原理上这跟相机的自动白平衡毫无差异啊。
那LightSpectrum Pro在什么情况有用呢？答案是在使用闪光灯时，我们可以先用手机APP粗略判断先场环境的色温，然后便可以使用相应的CTO Gel来调整闪灯的色温，来达致闪灯和环境光色温一致。
LightSpectrum Pro还有一个记录功能，需要时可以记下不同场景分析过的色温，方便将来参考。
下面是电影制作人Daniel Peters测试LightSpectrum Pro的视频，可以参考一下。
更多精彩视频内容，欢迎关注“拍电影网”官网及微信公众号^ ^
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