JPH06105224B2 - Raman spectrometer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a Raman spectrometer, and more specifically,
Prevents damage to the sample due to laser irradiation and enables in-situ
Even under (adjusted atmosphere), Raman spectroscopy can be performed efficiently and with good reproducibility. For example, inorganic or organic substances such as catalysts, glass and ceramics, or powders and compression molded products of these mixtures, films, etc. The present invention relates to a practically extremely advantageous Raman spectroscopic measurement device that can be suitably used in the field of Raman spectroscopic measurement of various samples such as molded products.

[Prior Art] Since Raman spectroscopic analysis is suitable for in-situ measurement, various cells have been devised. In particular, the surface structure of the catalyst is
Since it may be reformed in the gas processing part, changed during the reaction, or altered by the irradiation laser beam,
At least, development of a cell for in-situ measurement in consideration of these points is desired.

Conventionally, the damage to the sample due to laser light irradiation is suppressed as much as possible
As a Raman spectroscopic measurement apparatus having a cell for performing Raman spectroscopic measurement in-situ, a Raman spectroscopic measurement apparatus having a tilt-type rotary cell [GLSCHRADER, et al;
Spectroscopy.Volume 34, No2, p146 (1980)], Raman spectrophotometer with a tilt cell type rotary cell type using a cylindrical molded sample [GDJOHNSON; Applied Spectros
copy.Volume 31, No6, p565 (1977)] has been proposed.

In the Raman spectroscopic measuring device of FIG. 4, as shown in FIG. 4, the rotary cell A ′ has an inclination angle θ with respect to the optical axis direction of the condenser lens 9 ′, that is, the x direction. Is shown)) (i.e., having a tilted rotary cell A ').
In this way, the inclined type arrangement is inevitable because the laser beam 8'is provided below the sample holder 3'provided at the tip of the shaft end 2a 'in the optical cell 4'from the z direction.
This is because an optical system that irradiates the upper sample 10 'and collects the scattered light 12' by the condenser lens 9'is used.

However, in such a Raman spectroscopic measurement device having a tilt-type rotary cell, it is essential to adjust the tilt angles with respect to the x, y, and z directions in order to set the sample at an appropriate position. However, there is a serious problem that this adjustment is quite difficult.

On the other hand, in the Raman spectroscopic measurement device, the rotary cell A'is also used while being normally tilted, and the sample 10 is placed on the sample holder 3'at the tip of the shaft end 2a 'as shown in FIG. An optical system of a type in which a cylindrical molded sample is installed as ′, the side surface thereof is irradiated with a laser beam 8 ′, and the scattered light 12 ′ is condensed is used.

In this case, the rotary cell A'may be arranged horizontally in appearance, but it is necessary to form the sample in a cylindrical shape, and further, the narrow side surface portion 10a corresponding to the narrow angular range Δθ 'of the side surface thereof. Since it is necessary to irradiate the laser beam 8 ′ on the ′ ′, the adjustment angle θ ′ needs to be finely adjusted, and a problem occurs due to nonuniformity of the laser beam irradiation surface.

Further, generally, there is a problem that it is not always easy to form a powder sample into a cylindrical shape.

[Problems to be Solved by the Invention] The present invention solves the above-mentioned problems, and the optical axis alignment and the sample position determination can be easily performed only by adjusting in one direction (x-axis direction), and the sample is exchanged It is equipped with a rotary (vacuum) cell and its optical system with the arrangement state and configuration that have the excellent advantage that the same measurement conditions can be reproduced extremely well and easily even when moving or moving, Easily and reliably measure unshaped and molded samples in various forms such as powder, film, disk, pellet, etc. in-situ and while preventing damage to the sample by laser irradiation as much as possible. It is an object of the present invention to provide a Raman spectroscopic measurement device that is capable of performing and is extremely advantageous in practical use.

[Means for Solving the Problems] As a result of intensive studies to solve the above-mentioned problems, the present inventors have arranged the rotary cells in a horizontal arrangement, that is, collecting the rotation axis direction (movement direction) of the rotary cells. Optical axis direction of optical lens (x
Direction), the problem can be easily solved, and the alignment of the optical axis and the position of the sample can be easily performed only by adjusting in one direction (x-axis direction). It has the excellent advantage that the same measurement conditions can be reproduced very well and easily even when the sample is exchanged or moved, and it is in powder form, film form, disk form, pellet form, etc. A Raman spectroscopic measurement device that is extremely advantageous in practical use that can easily and highly reliably measure unshaped and molded samples of various forms in-situ and with minimal damage to the sample due to laser irradiation. By finding what can be realized, and by using an optical system in a specific direction as the optical system for irradiating the sample, the above advantages can be achieved particularly effectively. It found, and have completed the present invention based on these findings.

That is, the present invention has a horizontally arranged rotary cell A in which the rotary axis direction of the rotary cell A is matched or substantially matched with the optical axis direction (x direction) of the condenser lens 9, and the laser light is used. The Raman spectroscopic measurement apparatus is characterized in that it has an optical system for changing the angle of the light source 8 near the condensing lens 9 and irradiating the sample 10 in the horizontally arranged rotary cell A.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 schematically shows an example of a horizontally arranged rotary cell used in a Raman spectroscopic measurement device of the present invention.
(A) shows a partial cross-sectional view of a state in which the horizontally arranged rotary cell A is fixed to a mounting base B of the main body of the Raman spectroscopic measurement device as seen from the side direction, and (b) shows the horizontal direction. 1 shows a cross-sectional view taken along the line aa 'of an arrangement-type rotary cell A. FIG.

In the horizontally arranged rotary cell A illustrated in FIG. 1, the shaft 2 connected to the rotary shaft of the induction motor 1 has a magnetic seal unit 5 for maintaining a sufficient vacuum system inside the measurement chamber in which the sample is installed. It continues to the inside of the measurement chamber while being sealed by, reaches the optical cell 4 at the tip of the measurement chamber, and the sample holding portion 3 is provided at the end of the optical cell 4, that is, the tip of the shaft end 2a. .

The sample holder 3 can be appropriately rotated together with the sample 10 by operating the induction motor 1.

This rotation or the like can prevent the sample 10 from being damaged by the irradiation laser light.

A sample 10 is placed in the sample holder 3 as shown in FIG. 2 described later.

As the induction motor 1, a commonly used one can be used, and one suitable for the purpose, measurement conditions, etc. can be appropriately selected.

The magnetic seal unit 5 can be appropriately selected according to the desired degree of vacuum, etc., but normally, the structure and characteristics of the surface of the sample are easily changed by the air (especially oxygen) of the catalyst and humidity. When the measurement is carried out, it is desirable to make a sufficient selection especially in consideration of vacuum resistance, differential pressure resistance, leak amount, chemical resistance and the like.

Further, since the magnetic seal unit 5 is usually vulnerable to heat,
It is desirable to provide an appropriate cooling mechanism in order to avoid overheating due to a heating furnace such as the electric furnace 7. For example, by using a water-cooled type with good cooling efficiency, the maximum heating of the sample by the electric furnace 7 can be achieved. Temperature, for example, 600 ° C,
Alternatively, a higher temperature can be used.

The magnetic seal unit 5 of the horizontally arranged rotary cell A illustrated in FIG. 1 has a water cooling type cooling function, and the cooling water is configured to be supplied from the water cooling port 5a. There is.

As a specific example of the magnetic seal unit 5 that can be preferably used for in-situ Raman spectroscopic measurement of a catalyst or the like, for example, a magnetic seal unit manufactured by Rigaku Denki Co., Ltd. can be preferably used. The water-cooled type is usually 2,000 to 3,000 rpm and the helium leak amount is 10 ^-11 torr.
It has a performance of 1 / sec. Or less, a vacuum resistance of 10 ^-8 torr, and a differential pressure resistance of about 2.5 kg / cm ² .

On the other hand, the horizontally arranged rotary cell A is provided with a gas introduction part 6 for introducing a gas used for adjusting the atmosphere of the sample 10. The gas introduction part 6 has a gas introduction port. A nozzle extends to the vicinity of the sample holder 3 so that the gas introduced from 6a is introduced into the vicinity of the sample 10.

With such a vacuum system and gas introduction equipment, the atmosphere of the sample 10 can be suitably and easily adjusted at any time.
Pretreatment and in-situ measurement of the sample 10 can be performed accurately and efficiently.

Further, a thermocouple is arranged along the nozzle extending from the gas introduction section 6, and the tip of the thermocouple reaches the vicinity of the sample holding section 3, that is, the sample 10, whereby the thermocouple is always
It is possible to control or measure the temperature of the sample 10 or its immediate vicinity.

The horizontally arranged rotary cell A illustrated in FIG. 1 is provided with an electric furnace 7 so as to cover the outer side of the optical cell 4, whereby the sample 10 can be heat-treated at any time.

As the electric furnace 7, various types and performances can be appropriately selected and used according to the purpose. Specific examples include a resistance heating element, a semiconductor heating element, an infrared heating element and the like. However, it is usually sufficient to use a resistance heating element, for example, a maximum temperature of about 600 ° C. or higher can be easily obtained.

The electric furnace 7 illustrated in FIG. 1 employs a method of removing the electric furnace 7 when performing Raman spectroscopic measurement, but the present invention is not limited to this. For example, a front open type heater is used. By doing so, the measurement can be performed while heating.

As the optical cell 4, a commonly used one can be used, and its material, shape, etc. can be appropriately selected according to the purpose of use, conditions, etc. Usually, a quartz one is preferably used. can do.

Further, this optical cell 4 is, for example, 0-of Viton or the like.
A ring seal that can be easily attached and detached can be preferably used.

In addition, in the horizontally arranged rotary cell A illustrated in FIG. 1,
As the optical cell 4, a quartz cell that can be easily attached and detached using an O-ring seal made by Viton is usually used.

The Raman spectroscopic measurement apparatus of the present invention comprises a horizontally arranged rotary cell A as illustrated in FIG. 1, for example, a JASCO Raman apparatus NR-1000 or NR manufactured by JASCO (Jasco Corporation).
It can be obtained by mounting it on the main body of an existing device such as -1100 using the mounting base B.

Of course, the Raman spectroscopic measurement device of the present invention can be obtained by attaching it to a newly manufactured Raman device main body or by newly manufacturing it together with the device main body.

In the Raman spectroscopic measurement apparatus of the present invention, it is preferable that the horizontally arranged rotary cell A is normally attached horizontally as shown in FIG. 1, but it is not limited thereto. Instead of being a thing, it is also possible to incline with respect to what is called a floor, or to arrange so that it may become vertical.

That is, the horizontal arrangement type of the horizontal arrangement type rotary cell A in the Raman spectroscopic measurement device of the present invention means that at least the sample of the laser beam 8 irradiated on the sample 10 as shown in FIG.
The optical axis of the condensing lens 9 for condensing the Raman scattered light, that is, the scattered light 12 by the optical axis 10, that is, the x direction and the rotational axis of the shaft end portion 2a of the rotary cell A, that is, the moving direction of the sample 10 are the same or substantially the same. It means an arrangement state, and this x direction may or may not coincide with the horizontal direction of the spirit level.

FIG. 2 is a schematic diagram showing an example of the arrangement state of the horizontal arrangement type rotary cell A of the Raman spectroscopic measurement apparatus of the present invention and an example of an optical system near the sample holder 3.

In FIG. 2, the rotation axis of the shaft end portion 2a of the horizontally arranged rotary cell A and the optical axis of the condenser lens 9, that is, the x direction, coincide with each other. In order to adjust the position of the sample 10 installed on the end surface in the x direction of the sample holder 3 provided in the above, the horizontal arrangement type rotary cell A is moved relative to the x direction in a relative arrangement state. As described above, in the optical system illustrated in FIG. 2, the laser light 8 emitted from the objective lens 11 is changed in angle in the vicinity of the condenser lens 9 by using the reflecting mirror 13. The sample 10 is irradiated.

That is, in the present invention, one of the important points is the second
As illustrated in the figure, the point is to use an optical system characterized by changing the angle of the laser beam 8 with which the sample 10 is irradiated near the condenser lens 9.

In this way, by changing the angle, the sample 10 in the horizontally arranged rotary cell A is effectively irradiated with the laser light 8, and the scattered light 12 is more effectively condensed on the condenser lens 9. can do.

Further, by using such a specific optical system or optical arrangement, the position of the measurement surface of the horizontally arranged rotary cell A or the sample 10 can be determined remarkably easily and with good reproducibility only by adjusting the x direction. be able to.

It is extremely easy to adjust and control the angle of the laser beam 8 to an optimum value or the like, and it can be performed quickly.

The method of changing the angle of the laser beam 8 is not limited to the example of using one reflecting mirror 13 shown in FIG. 2, and for example, a method of combining a plurality of reflecting mirrors and a method of using a prism. Various methods such as a method of combining them can be used.

By the way, once this angle is adjusted, since the rotary cell A of the present invention is set in the horizontal arrangement type, its position can be changed by a simple operation of moving the rotary cell A in the x direction. The rotary cell A can be adjusted easily and with high accuracy, and even when the horizontally arranged rotary cell A is moved or the sample is changed.
Alternatively, the position of the measurement surface of the sample 10 can be easily reproduced with high accuracy.

In the Raman spectroscopic measurement device of the present invention, the sample 10 can be used in various forms such as powder, disk, pellet, flat plate pellet, and film.

Among these, compression-molded flat-plate pellets can be preferably used.

By using this compression-molded flat-plate pellet-shaped sample, it is possible to obtain a uniform measurement surface and ensure good reproducibility when supporting the sample-holding section 3.

Further, by adopting the above-mentioned horizontal arrangement type rotary (vacuum) cell A, adopting the above-mentioned specific optical arrangement, and using the sample in the form of a flat plate pellet, it is particularly preferable to determine the position by adjusting only the x direction. The same measurement surface can be obtained even with different samples, and particularly excellent Raman spectroscopic in-situ measurement can be realized.

In addition, in the Raman spectroscopic measurement device of the present invention, as an example of an optical system near the sample holder 3 of the horizontally arranged rotary cell A, a backscattering optical system (backscattering holder) as illustrated in FIG. Can be preferably used.

In the backscattering holder illustrated in FIG. 3, the laser light 8 is refracted by the prism 14, and then two objective lenses are used.
An optical system is adopted which, after passing through 11 and 11b, changes the angle by a reflecting mirror 13 and guides it to the sample 10 in the horizontally arranged rotary cell A.

At this time, the focus can be adjusted by moving at least one of the two objective lenses 11 and 11b in the direction of the arrow in the drawing.

Further, the angle of the laser beam 8 can be adjusted by the reflecting mirror 13.

As this backscattering optical system, for example, a system manufactured by JASCO Corporation can be preferably used.

Example 1 Example 1 The horizontally arranged rotary vacuum cell A shown in FIG. 1 was combined with a JASCO Raman apparatus NR-1000 (manufactured by JASCO Corporation) and the backscattering holder shown in FIG. 3 to perform the following measurement. It was About 10% by weight of molybdenum trioxide (M ₀ O ₃ ) was crushed on a catalyst (M ₀ O ₃ (10) / Al ₂ O ₃ ) supported on γ-alumina, and the diameter was 10 m.
It was molded into a flat plate of m. The sample was held in the sample holder 3 in the optical cell 4 shown in FIG. 1 and directly measured by the Raman apparatus. The Raman measurement result is shown in FIG.
A non-logarithmic peak was observed around 960 cm ^-1 .

Next, the sample is taken out with it kept in the optical cell 4, and while flowing dry air from the gas inlet (40 to 60 cc / min) at 400 ° C. for 2 hours.
Burned for hours. After that, the gas was changed from air to helium, and after allowing to cool to room temperature, it was attached to a Raman apparatus and measurement was performed under the same conditions as described above. The results are shown in FIG. 6 (b). The peak at 960 cm ^-1 in (a) is 990 in (b).
Shifted to ~ 1000 cm ^-1 . (A) also once in air 550
This change is not a structural change due to heat because it was baked at ℃, and since the one dehydrated at 400 ℃ is in the in-situ cell, it can be measured as it is without touching the air during measurement. Considered to be In other words, the peak appearing at 960 cm ^-1 sucking water vapor in air, was confirmed to be shifted to 1000 cm ^-1 when dried.

Example 2 After measuring FIG. 6 (b), hydrogen was flown while the sample was kept in the cell to raise the temperature to 100 ° C., 300 ° C. and 400 ° C. to reduce the catalyst. The Raman spectrum of each is shown in FIG. Start peak was in 990 cm ^-1 decreases with proceeds reduced, a new peak appeared in the vicinity of 800 cm ^-1 (300
It was found that this also decreased at 400 ℃.

As described above, in the in-situ cell, a substance that is deteriorated in air and cannot be measured correctly can be measured in the in-situ cell without touching the air.

Also, in this horizontally arranged rotary cell A, once the sample position is determined, the main body is removed from the Raman device,
Even if various other processes are performed, the measurement at the exact same optical position can be performed when the sample is mounted next time if the x-axis position of the sample is combined with the previous time. Of course, it is also possible to perform processing with the Raman device installed.

Further, it was found that it is possible to directly measure the change of the sample when treated with hydrogen gas as in Example 2.

The Raman spectroscopic measurement devices used in Examples 1 and 2 are all made of SUS and quartz, and thus have an advantage that a corrosive gas such as hydrogen sulfide can be used. .

[Advantages of the Invention] According to the present invention, the optical axis alignment and the sample position determination can be easily performed only by adjusting in one direction (x-axis direction), and the same measurement can be performed even when the sample is exchanged or moved. It has excellent advantages such as being able to reproduce conditions extremely well and easily, and it can be used for in-si-forming of unshaped and molded samples of various forms such as powder, film, disk, and pellet.
It is possible to provide a practically remarkably advantageous Raman spectroscopic measurement device that is a tu and that can easily and highly reliably perform measurement while preventing damage to a sample due to laser irradiation as much as possible.

[Brief description of drawings]

FIG. 1 (a) is a partial cross-sectional view schematically showing an example of a horizontally arranged rotary cell A of the Raman spectroscopic measurement device of the present invention and an example of its mounting state, and FIG. 1 (b). Is
It is the aa 'sectional view. FIG. 2 is a schematic diagram showing an example of the arrangement state of the horizontal arrangement type rotary cell A of the Raman spectroscopic measurement apparatus of the present invention and an example of an optical system near the sample holder 3. FIG. 3 is a schematic diagram showing an example of a backscattering optical system that can be used as an example of an optical system in the vicinity of the sample holding portion 3 of the horizontally arranged rotary cell A of the Raman spectrometer of the present invention. is there. FIG. 4 is a schematic diagram showing an arrangement state of a tilt-type rotary cell A ′ of a conventional Raman spectroscopic measurement device and an optical system near the sample holder 3 ′. FIG. 5 is a view showing an arrangement state of a normally tilted rotary cell A'of a Raman spectroscopic measurement apparatus of a type in which a laser beam is irradiated within a specific angle range on a side surface of a conventional cylindrical molded sample, and a sample holder 3. It is a schematic diagram showing an optical system near '. The symbols in the figure are: A: Horizontally arranged rotary cell, A ': Tiltly arranged rotary cell, B: Mounting base, 1: Induction motor, 2: Shaft, 2a, 2a': Shaft end part, 3,
3 ': sample holder, 4, 4': optical cell, 5: magnetic seal unit, 5a: water cooling port, 6: gas inlet, 6a: gas inlet, 7: electric furnace, 8,8 ': laser light , 9,9 ': Condensing lens, 10,1
0 ': sample, 11,11', 11a: objective lens, 12,12 ': scattered light, 13: reflecting mirror, 14: prism, X: x direction, Y: y direction, Z: z
Direction, θ: inclination angle, θ ′: adjustment angle θ ′, Δθ ′: angle range Δθ ′. FIG. 6 and FIG. 7 are charts showing Raman spectra measured in Example 1 and Example 2, respectively.

Claims (1)

[Claims] 1. A condenser lens 9 is arranged in the direction of the rotation axis of the rotary cell A.
Has a horizontally arranged rotary cell A that is aligned or substantially aligned with the optical axis direction (x direction) of the laser beam, and changes the angle of the laser beam 8 near the condenser lens 9 to rotate the horizontally arranged type. A Raman spectroscopic measurement apparatus having an optical system for irradiating the sample 10 in the formula cell A.