1. High Spatial Resolution Nonlinear Spectroscopy of Near-Critical Fluid in Pores of Nanoporous Glass
International Laser Center and Physics Department of
M.V. Lomonosov Moscow State University, Moscow , Russia

2. Transparent nanoporous materials
glass
zeolites
Pore radius:
~1 … ~100 nm
Width of pore radius distribution:
down to Angtsroms
aerogel
polymeric
Porosity: up to 99 %
Surface area:
up to ~1000 m2/g

3. Nanoporous glass Vycor DV-1M Unit weight 1.5 g/cm3 Void space 28%
Internal surface area m2/g
Average pore radius nm (r~0.5 nm)
9 mm
4 mm
DV-1M
d, nm
Unit weight g/cm3
Void space %
Internal surface area m2/g
Average pore radius nm (r~0.5 nm)

4. Fluid inside a nanopore at different pressures
gas
1st adsorbed
layer
liquid-like layer
+ condensed phase

5. Supercritical fluid (SCF)
symmetric
stretch
asymmetric
bending
1335 cm-1
0220
2003 cm-1
0330
1000
2000
cm-1
1388 cm-1
1285 cm-1
0200
667 cm-1
0110
2077 cm-1
1110
1932 cm-1
0310
0000
CO2 vibrational energy levels ν1 ν2 ν3
solid
liquid
Supercritical fluid (SCF)
TCR=31.1 oC
(no gas-liquid transition in bulk)
TRoom is near-critical
PCR
Critical point
PCR=72.8 atm
Triple
point
gas
pressure
temperature
TCR

6. CARS spectra at room temperature
pore radius:
2 nm
3.5 nm

7. Experiment and calculations
pore radius:
2 nm
pressure, atm
adsorption 32
~1.3 monolayers
(d=0.5 nm) 48
~1.8 monolayers
(d=0.7 nm) 52
~2 monolayers
(d=0.8 nm)
condensation
in pores 55
condensation
in bulk 58

8. CARS spectra at near-critical temperatures
spectral contributions
subcritical 30.5 oC
supercritical 33 oC
Manifestation of critical point shift

9. CARS spectra at 22 C at low pressures
pore radius:
2 nm
liquid-like fluid
gaseous fluid
surface-adsorbed
fluid