Yin Li

7 Questions 34 Answers 0 Followers

Questions related from Yin Li

Do I need to further optimize the geometry which was obtained from experimental measurements in vibrational calculations?

Hi, everyone! I want to calculate vibrational spectra (IR and Raman) of a crystal. I downloaded the cif file which contains the information of lattice and fractional coordinates from a database....

05 May 2015 3,115 8 View

How to define a crystal structure in quantum-espresso (pwscf)?

In the tutorial of quantum-espresso (pwscf), the tutor demonstrated how to set up a unit cell using the parameters list below. ibrav=2, nat=1, ntyp=1 Only 1 atom is enough to define this...

03 March 2015 1,888 25 View

What does the appearance of 2G and D+G band in Raman spectra of multi-walled carbon nanotubes indicate?

Some of my received MWCNT showed 2G and D+G band in their Raman spectra? Is that normal? Or those MWCNT have already been damaged somehow?

05 May 2014 5,533 10 View

What are the appropriate laser power and exposure times for confocal Raman measurement of carbon nanotubes?

There is a confocal Raman equipment at our lab. The full laser (633 nm) power is 25 mW. I am worried that too intensive laser would damage the tubes. According to experience, what are the...

04 April 2014 7,324 4 View

When the excitation spectrum is different from adsorption spectrum, whose maximum wavelength should be involved in stokes shift calculation?

My compound shows the maximum absorbance at around 260 nm. But the maximum intensity in excitation spectrum appears at 300 nm. The excitation spectrum has been corrected. I wonder which maximum...

11 November 2013 7,374 14 View

Can ultrasonicator cut long carbon nano-tubes into shorter tubes or break them into small graphene pieces?

I used an ultrasonic bath (30 kHz, 120 W) to disperse my carbon nano-tubes in SDS solution. The AFM image shows many small white areas. I am thinking on those white areas could be caused by...

11 November 2013 3,931 29 View

Of PL, UV, Raman, which method is the most sensitive for the detection of individual single-walled carbon nanotubes?

I want to get individual single-walled carbon nanotube (CVD) in water by using 1wt%SDS. I have tried the most powerful experimental methods in my lab including 200W tip-type sonicator for 3 h as...

11 November 2013 8,185 5 View