実験報告書様式（一般利用課題・成果公開利用）
提出日 Date of Report

MLF Experimental Report

2013/03/20

課題番号 Project No.

装置責任者 Name of responsible person

2012B0201

Toru Ishigaki

実験課題名 Title of experiment

装置名 Name of Instrument/（BL No.）

The determination of structure and rotational motion of CCl4 in

BL20

confined spaces

実施日 Date of Experiment

実験責任者名 Name of principal investigator

2013/02/11-2012/02/13

Taku Iiyama
所属 Affiliation
Faculty of Science, Shinshu University
試料、実験方法、利用の結果得られた主なデータ、考察、結論等を、記述して下さい。（適宜、図表添付のこと）
Please report your samples, experimental method and results, discussion and conclusions. Please add figures andtables for better explanation.
1. 試料 Name of sample(s) and chemical formula, or compositions including physical form.
The original designed measurement cell for the measurement with cryostat of BL20 was used. The 1.10 gof ground activated carbon fiber A20 (Ad’all Co.; pore width is 1.13 nm) was introduced in the cell, andpreheated for 4h at 393 K and 1 mPa before the measurements. Then CCl4 vapor was introduced to the cell.
The amount adsorbed is 2.52 g which is corresponded to saturated adsorbed amount. We measured theneutron diffractions of this CCl4 adsorbed A20, and also bulk CCl4 and A20 (298 K) itself. The measurement
time is 100 m with 300 kW pulsed neutron beam, at double-frame mode. ND of CCl4 adsorbed activatedcarbon A20 (φ = 1) was measured at 255, 238, 221, and 100 K in cooling process, and at 135, 170, 187, 204, 221,
238, 255 ,273, 290 K at warming process. ND of bulk CCl4 was measured at 221, 238, 255 K.

2. 実験方法及び結果 （実験がうまくいかなかった場合、その理由を記述してください。）
Experimental method and results.

If you failed to conduct experiment as planned, please describe reasons.

In this experiment, we tried to determine the structure and its temperature dependency of CCl4 inhydrophobic small space.

CCl4 is a spherical molecule,
1.6

and have a long-range ordered structure even in a liquid

1.4state at room temperature. The diameter of CCl4
microporous carbons (around 1.0 nm).

A molecular

packing should be sensitive to the pore width.
Furthermore, CCl4 has a plastic crystal phase between
225 and 250 K. The rotational motion of CCl4 moleculeCCl4 adsorbed AC at 290 K

1.00.80.60.4bulk CCl4 at 290 K
0.20.00will be strongly affected by the space restriction.

10000 20000 30000 40000 50000 60000 70000 80000

tof / µs

We measured ND of CCl4 adsorbed activated carbon(AC) at fractional filling φ = 1.

1.2

Intensity, S

molecule (0.59 nm) is comparable with pore width ofThe AC sample waspreheated in the cell, and then CCl4 vapor was1Fig.1 ND profiles of bulk CCl4 and CCl4
adsorbed AC (SE bank)2. 実験方法及び結果（つづき） Experimental method and results (continued)
introduced. Equilibrium time was 2 day.

The ND was0.5

measured between 290 and 100 K every 17 K in warming
0.0290 – 221 K) were also measured. Measurement time-0.5

was set 100 min with 300 kW pulsed neutron beam atln Sprocess. The ND of AC itself (at 298 K), and bulk CCl4 (atdouble-frame mode.

CCl4 adsorbed AC at 290 K-1.0

bulk CCl4 at 290 K-1.5

Fig.1 shows the ND profiles of bulk CCl4 and CCl4-2.0

adsorbed AC at 290 K. The all ND profiles of bulk CCl40.0000

0.0005and CCl4 adsorbed AC show that decreasing intensitywith tof increasing. It will become from the absorption ofneutron by the sample itself, because the Cl atom has

221 K
238 K

0.6

0.0025

255 K
290 K

0.4

4πr 2(r(r)-r0)

We tried to correct of this effect using follow relation.
The cross section of thermal neutron absorption isinverse proportional to the velocity of neutron.
𝐼/𝐼0 = exp(−𝑁𝛼𝑥/𝑣)

0.2

0-0.2

Fig 2 shows the plot of log I vs 1/v. The linear relation-0.4

0in this plot means that the absorption coefficient is
We used this relation for the1.6

CCl4 adsorbed ACS(Q)

0.8

K show the sharp peaks due to the crystal structure, but

0.6

ACBulk CCl4 (290 K)
0.4
0.0

1.0

profiles in this analysis. The profiles show clearly theof peak at 0.4 nm show the strong dependency with T, this

100 K
170 K
221 K
255 K
290 K

1.0

The ND profiles of bulk CCl4 at 221, 238, and 255

molecular shape and its ordered structure. The intensity

21.2for the averaged profile of all temperature.

periodic peaks at 0.6, 1.1, 1.5, 2.0 nm due to the spherical

1.5

1.4

temperature; therefore, it was obtained by the line fitting

we obtained RDF by the same procedure for the liquid

1Fig 3 RDF of bulk CCl4

𝐼′ = 𝐼 ∙ exp(𝑁𝛼𝑥/𝑣)

Fig 3 is the radial distribution functions (RDF) of bulk

0.5

r / nm

We assumed that the coefficient 𝑁𝛼𝑥 is constant in all

CCl4.

0.0020

Fig.2 Reciprocal relation between ln I vs v.

33.5, the other concerning atoms (C, D) are nearly 0).

correction of thermal absorption.

0.0015(1 / v) / s m-1

a high thermal absorption cross section σabs (σabs(Cl) =proportional to 1/v.

0.0010

2.0

3.0

4.0

5.0

Q / A-1

Fig.4 corrected ND profiles of CCl4adsorbed AC (SE bank)peak is attributed to Cl-Cl distance of near-side of neighbor molecules.

It is indicated that the rotationalmotion of CCl4 can be detected by the neutron diffraction. Fig 4 shows the corrected ND profiles (usingMAT00XX.SE.bin02Double_0.histogramIgor).

The adsorbed samples show the high-Q shifted 1st peak (atQ=1.3 A-1) and low-Q shifted 2nd peak (at 2 A-1). The peak position and shape of these peaks changes with T
clearly in wide T-range. These peaks are attributed to the intermolecular structure of adsorbed CCl4. We
will elucidate the detailed structure of that using RDF and RMC analysis.
2